While I agree, the amount of people who'd do this is negligibly small, compared to their total userbase. Obviously a bunch of people use ad blockers, but only a tiny amount of them have modified apps, followed by an even tinier amount of those people with fully custom frontends. For YT it might work out as a net positive, because the annoying blocks and reminders will just pressure people into paying for Premium.
At the end of the day, I could just stop watching youtube entirely, if this trend continues. I have nothing to gain there