Slow, compact primes worthy of their sensors. All too easy
I agree that there won't be many F-mount lenses from here on out. For the next 2-3 years, Nikon critically needs to get Z lenses out, and they've publicly committed to doing so with the roadmap. Sure, it isn't legally binding, but it'd be severely embarrassing for them to not come pretty close to what they've promised.
And in 2-3 years, when they'd have the option to ease up a bit, mirrorless will have taken over current sales, and projections for a lens' ~8 year lifespan will be even more favorable to mirrorless. Why would they revert to legacy production then?
They're not going to say the quiet part--everyone rebuying their lens kits in Z mount is *great* for Nikon--aloud, but it's not too hard to imagine it said in headquarters meetings...