Gene Wilder left a lasting image in his many movie roles and that will continue to entertain future generations. He had not been active toward the end of his life due to Alzheime's disease. One of the advantages of comedy is that is it timeless and watching his films will be an enduring legacy. The younger generation will need to explore his films.
Yes! Of course people remember the actor, Gene Wilder! Was he the hottest and biggest name just recently before his unfortunate passing? No. Was he right at the top of every young person's list of favorite actors? Probably not. However it is my opinion that the vast majority of people will remember the actor fondly for all time due to the strange but likable roles he played.
People may remember Wilder from his days at SNL, his earlier movies, the brilliance that was him and Richard Pryor, or they may remember him more recently from movies like Willie Wonka and the Chocolate Factory. Someone with his level of skill, who jumped off the screen, isn't going to be forgotten anytime soon.
It's documented that Gene Wilder was living until August 2016, yet people still say they thought he died, although they can't produce any news reports about this. We've only seen people who were alive but who people thought had died (and practically always older people, who you'd be forgiven for thinking they had died).