I’m inclined towards the belief that genericide happens far less frequently than is believed (aspirin, escalator, zipper, yo-yo , thermos (with an asterisk) and very few others). Today’s NY Times ran an obituary of the inventor of the trampoline which makes the claim that George Nissen, added an ‘e’ to the Spanish word for diving board, trampolin, and registered the word as a trademark. Several other sources on the Internet repeat this.
I can find trademarks filed by Nissen and his company on TESS, but I can’t find a cancelled trademark for TRAMPOLINE covering ‘backyard tumblers’ owned by anyone. If you have info on the genericide of TRAMPOLINE, please share.