Population decline is bad for the species because the endgame of population decline is population == 0.

That's a slippery slope argument which doesn't hold up. There are many endgames and goals. Managed properly, the human population will equal 0 someday because we will have further evolved into something else.

> the human population will equal 0 someday because we will have further evolved into something else.

Ah, there are other possible paths. 1) Extinction (which has happened to many species) without any evolutionary successors. 2) Artificial life (it evolves without us). 3) Something else evolves (long after we are gone) and becomes the dominant species on the planet.

Humanity has limited options, but nature doesn't and we can't count on it doing us any favors.

"...there are other possible paths..."

Hence @quantified's "managed properly" caveat.

I don't want that. I'm a Human supremacist and I don't want to be an em.

> Managed properly

What makes you think it's being managed properly? Fertility rate 0.78 in Korea signals uncontrollable plummet to 0. TFA: 1.2 million small businesses have owners aged about 70 with no successor, prime minister Fumio Kishida: "Our nation is on the cusp of whether it can maintain its societal functions" - sounds anything but managed properly

The fact that people enjoy sex means we will never hit zero. Plenty of people will always remain.

Hmm, is population decline inevitable? With sufficiently large time scale. If it is, would it be better for species to exist longer time or peak at larger numbers. Or maybe some per specime x time total?

I would argue peaking hard and crashing hard by overshooting is worse than peaking slower and then steady very long decline.