I don't think anyone here is arguing the position that LSD will have a profound impact on anyone who takes it, just that it can give people a different way of looking at the world and sometimes that leads to novel and important insights.
Replace "LSD trip" with "university degree" in your example. Sure, there are many people who take a physics course and feel as though they have had profound insights but actually haven't. However, you can't use those examples to argue that everyone who claims their physics course has inspired their life and work is lying.
I think the psychedelic experience at most produces an unwarranted sense of the profound. You may feel like revelations have occurred, but really they were nothing. Like those dreams when you figure it all out but when you wake up it's gone, or it was something about wearing your trousers backwards to solve the problem of disharmony in the middle east.
That's not to say I don't think there are a whole load of positives in there, but deeper understanding of the universe and yourself? Meh, I say, meh.
Even in my limited experimentation with drugs, I feel as though I've experienced thought outside the realm of regularity.
It's not only LSD that does it either, other drugs do it, as do some activities. People with a lot of practice in meditation seem to develop the same feeling, from the way they describe it.