But Feynman, like many other intelligent, famous people, had a bad habit of opining on and dismissing out of hand subjects he knew little about. He did this with philosophy and with psychedelics.
At least he tried LSD, but he was clearly not an authority on LSD, and his experience with it was minimal. Not to mention that back in the 60's little was known about how best to use it (there was some research in to this, but most people were not aware of the most effective methods.. and even now, while we know better we might not have the optimal method figured out).
While Feynman might not have solved his scientific problem on that particular session that doesn't mean that it's useless in helping problem solving. In fact, there has been research that indicated that it helped with both creativity and problem solving: [1][2] and there's still ongoing research in to this subject.[3][4]
As we all know today, the benefits of psychedelics can extend far beyond helping with creativity and problem solving, however.. they can help with various personal and mental issues, for example, increase empathy and openness, help with end-of-life anxiety, help with relationships, etc... apparently Feynman was either completely ignorant of this potential or chose to ignore it while focusing only on the narrow subject of scientific problem solving and his fear.. which is understandable, but not really a fair assessment of the potential of psychedelics.
Which isn't to say that Feynman should have taken more LSD (that's a personal choice for everyone, and I respect his decision).. but just because Feynman didn't doesn't mean no one should.
[1] - https://www.amazon.com/LSD-Spirituality-Creative-Process-Gro...
[2] - https://maps.org/news/media/4814-jim-fadiman-on-psychedelics...
[3] - https://sciencetrends.com/does-microdosing-lsd-stimulate-cre...
[4] - https://maps.org/news/multimedia-library/3171-can-psychedeli...
That said, this is a wide open field that could greatly benefit from more research. I am hopeful that such research will once again become acceptable to the scientific establishment before too long, as a number of studies on other effects of psychedelics have recently been completed with much success.
[1] - https://www.amazon.com/LSD-Spirituality-Creative-Process-Gro...
[2] - https://www.amazon.com/Psychedelic-Explorers-Guide-Therapeut...
That said, it's not a panacea or a magic pill. You are not guaranteed to become more creative when you take LSD. You most likely will not become Mozart or Picasso by taking it. It is even possible to misuse or abuse LSD, as you can misuse and abuse alcohol, food, water, and sex.
My own observations of people having unproductive experiences from psychedelics is that they take them in ignorance, without much if any education about what they're taking, without proper respect (ie. to just "party" or "have fun" or as attempted distractions or escapes from lives that are miserable in various ways), in an unsupportive or even actively hostile context, without planning, and without a goal.
They often believe in all sorts of urban myths about LSD and other psychedelics (like that taking LSD seven times makes you "clinically insane", or that LSD damages your chromosomes or makes you stare in to the sun until you go blind, etc), they often mix drugs (which can be very dangerous -- especially when one of those drugs is alcohol), and do really stupid things like driving under the influence.
Is it any wonder that such situations and attitudes lead to bad outcomes? Should drugs be blamed for what happens? Or could some responsiblity for what happens be laid on the shoulders of the people who choose to use them in stupid ways, or on the society that keeps them ignorant or tries to lie about the effects of these drugs or actively tries to harm drug users, or at least make constructive, safe use of these substances very difficult and dangerous?
About your friend who was "sectioned" (I presume this refers to involuntary confinement to a mental institution), it sounds like you know very little of what actually happened to him or his psychological state before or after the incident. I would not be surprised if his family (who you admit have had mental problems of their own) or the authorities overreacted, and that his confinement to the mental institution might have been a much worse experience than his LSD trip.
Finally, an LSD trip can be a very emotionally intense experience. Emotionally intense experiences of any kind could trigger psychotic episodes in succeptable individuals. Such people could have a psychotic episode without any being drugs involved. People with family history of mental illness would do well to be extra cautious before engaging in any activity that might result in an emotionally intense experience.
[1] - http://www.amazon.com/LSD-Spirituality-Creative-Process-Grou...
On the contrary. There have been a number of studies which have provided evidence that psychedelics can, in fact, lead to spiritual or mystical experiences.[1][2][3][4][5]
Now, that isn't to say that when you take psychedelics you are guaranteed to have a spiritual or mystical experience (or any other kind of experience). The effects of these substances are just too varied, not well enough understood, and not fully under our control. However, you can prepare for and structure the experience such that the likelihood of spiritual or mystical experiences increases.
[1] - https://en.wikipedia.org/wiki/Good_Friday_Experiment
[2] - http://www.erowid.org/plants/mushrooms/mushrooms_journal2.sh...
[3] - https://www.erowid.org/chemicals/psilocybin/psilocybin_artic...
[4] - http://www.amazon.com/LSD-Spirituality-Creative-Process-Grou...
Countless artists, writers and musicians were influenced by psychedelics. It's not hard to make an argument that the music most people listen to and love today would not exist without the influence of psychedelics.
The Beatles are just one super famous example, where the influence of psychedelics on their music is super obvious and the tremendous influence of The Beatles is undeniable, but the same could be said of many if not most 60's/70's musicians, which in turn had huge influence on what followed, not to mention the obvious influence of psychedelics on psytrance and dance/club music in general.
Something else to consider is that from the time psychedelics were outlawed until very recently admitting psychedelic use was taboo, and so many psychedelic users were in the closet.
These are more open times, so some people are admitting it now, but many are still in the closet because coming out as a psychedelic user could still negatively impact your job prospects, the way society in general views you, and perhaps your relationships with people you care about.
So there are probably way more psychedelic users out there than most people realize, and their accomplishments when taken as a whole are very significant.
How much of such accomplishments were due to the influence of psychedelics? We don't have enough information to say for certain, but there have been studies on the effects of psychedelics on creativity[1][2][3] which show a positive effect. That's not to mention the well demonstrated potential of psychedelics to help with depression, the alleviation of which could also help users to create and contribute to society.
[1] - https://pubmed.ncbi.nlm.nih.gov/35105186/
[2] - https://pubmed.ncbi.nlm.nih.gov/2723891/
[3] - https://www.amazon.com/LSD-Spirituality-Creative-Process-Gro...