Gnomes never had grace to fall from.
I know this has come up before, but it's worth repeating. Gnomes suffer greatly from the lack of an easily identifiable mainstream fantasy archetype. Even before they were hated, at least IME, they were never particularly well liked. They were just there.
Then tinker gnomes came along. If the gnomes had begun in a position of popularity, it's possible the tinkerers wouldn't have harmed them as much as they did. But gnomes started from a position of, at best, amiable neutrality in the minds of most players. (Again, IME, anecdotal evidence, etc.) So it was real easy for an ultimately goofy archetype to catch on, and refuse to let go.
To this day, I'm trying to reintroduce gnomes into some of my homebrew settings as a truly worthwhile race, but it's a struggle to get my players to accept them as such. And frankly, it's a struggle that I'm only half-heartedly fighting, because I'm still not all that enamored of them myself.