I'm sorry but I can't let this one slide. Yes, children have been subjected to a slew of execrable sitcoms but at least in the realm of cartoons children's there is much that is of high quality. Adventure Time, Gravity Falls and Steven Universe roundly refute "universally terrible". Even the 2000s had Avatar, Samurai Jack, early Spongebob and Fairly Odd Parents. Other than nostalgia and smugness, I can't find any justification for claiming that none of it was as "mentally stimulating" as the 90s given how equally rife with garbage the 90s were.