It's only the sale of them. People keep their cars for 10-15 years. If we don't even stop selling them in 2035 they'll still be on the roads past 2050.
Given all the loopholes and the lifespan of modern cars, I would say 2035 is ridiculously late and it should have been 2025 or 2030 at most.
Gasoline sale is already plummeting by up to 30% a year some places in Norway. The people who drive the most are the first to convert to EVs since the economics make more sense for them, and newer cars get driven more than very old ones. So EVs will soon dominate the number of miles driven and thus the impact on fuel sale will be larger than you'd think.
By 2025 I think you'll start to see gas stations closing down in Norway. By 2035 you'll see the same across Europe. You'll still have gas stations here and there. But it's not going to be as close and convenient as it is now. Even just a few gas stations closing down will get people to panic about whether they'll have a local gas station in the near future. Who will want to buy a new ICE vehicle in that situation?
Sure, there will be some enthusiasts. But not enough that it's worth thinking about.
But I do wonder about the the gas stations. It is well known, that gas stations make most of their money on snacks and carwashes and random stuff you buy and not on the gas. Does that break down or will people in EVs still stop in gas stations to buy a snack? Maybe on roadtrips yes, on random visits no?
Will there be small shops selling snacks and coffee next to charging stations as well? Could gas stations pivot to being charging stations? (I guess not the inner-city ones, due to space, but the highway rest stop ones could).