This is a really funny joke, but with global population decline in first world countries this is going to be a big issue. Incentivizing people to care for a world they're not going to be around for is going to be fun
The most impactful single decision one can make in terms of not making things even worse is not reproducing. It is the single most sustainable decision in terms of resource use, pollution and climate change.
The fact that people are voluntarily doing this is good, the presupposed "dangers" of population decline are dangers to the systems that demand infinite endless growth, which I would argue are dangers to people in the first place. Fuck 'em.
Some maybe, but it isn't like people who have kids have that good of a track record. No reason to believe people without kids are especially probelmatic.