Ready for a fairly philosophical conversation about a snail;Hilarious
Well I think it comes down to what you identify as stupidity which I'm not sure is what I'd call this because most mollusk lack the intelligence needed to be stupid as far as I'm aware. Some may argue stupidity is the lack of intelligence but I think its better defined as a lack of intelligence where it is needed.
For instance these snails only exist because they have evolved well enough to survive the habitat they are naturally found in. Many living things are extremely successful because intelligence isn't needed to survive where they are from. On the opposite side of that you have humans whose "intelligence" is so misused it ends up wiping out surrounding species and our own. That includes taking living thing out of its natural environment and putting it in a situation it has never had to deal with before and when it perishes because it can't process things to our standard of intelligence we label it as dumb or stupid.
Whats actually happening (The most painfully simplified version) is Everything that exist only exist because it eats something and something else eats it. their evolution to survive threats takes energy from thousands if not millions of generations of their own kind, energy that would not be spent on something unless it was 100% necessary to survive. If they can't flip themselves over its because where they come from the amount of things that can nock them over is so insignificant that it makes more sense to lose a small portion of their population than to waste the precious energy they need to stay alive on changing something that doesn't help them survive in the only place that matters- the wild.
I think better arguments could be made for the lack of human intelligence in realizing this flaw, deciding to take them and put them in environments they could never prepare for or comprehend and then for generations of exchanging the same information deciding to put resources into continuing to do it instead of looking at better suited species that are capable of flipping themselves over in the wild and therefor more equipped to handle the strange environments we force them to exist in (Unless your snail signed the proper consent forms which would raise more questions than the number of snails in existence).
I really hope I don't come across as rude, I'm not trying to single you out or anything like that, just trying to raise a perspective I find many people don't consider.
I was under the impression that trochus were a kind of snail that could flip themselves over, I could certainly be wrong though.