OP asks: why so many people are now convinced that we are living in a simulation?

Not whether we think we do or don't.

Which is a quite different question.

For my 2 pennies, whether or not it makes a difference (as mentioned in simulation argument) does itself not matter, all that matters if people think it matters (it is, after all, entirely in our head at this point). Does it create a disassociation effect where counter-intuitively a constructivist approach allows is to see the world more positively (positive, as in positivist). And if not, are poll answers blunder or is there no disassociation of self determination.