I dunno. There’s often very little you can do to avoid traveling with a child when you have responsibility for little ones for any reason, especially since so many times wherever you’d bring a child it’s a place where the child being there is kind of important. Seems unfair and socially short-sighted to make it any harder to raise a kid than it is and I say that as someone who already looked at the concept of parenthood and thought:
“Old endgame lost of old, play and lose and have done with losing."
BUT I would 100% sincerely pay extra for a no kids extra legroom flight. That is a way better value than “business class” or whatever they call it now. For international travel options like that priced between 1st class and economy for 12 hours or whatever no kids even if it required extra layover that’d be nice. I suspect if it was actually financially feasible some one would be doing it by now, but maybe not in the US because that also seems likely to attract lawyers.
I’ve had way too many sick (vomiting), angry (screaming), bored (literally pulling my hair, pinching, grabbing, kicking), and so on kids to be unsympathetic because modern planes are so cramped these people are practically in your lap for 9+ hours. But such are the hazards of public transportation 
It’d also be nice not to run into unruly drunks kwim? But good luck with that while flying frequently…
Generally exclusionary policies work best if the people being upsold on the experience are the ones to pay for it (that’s punching up not kicking down I think). So if someone wants a guaranteed no screaming babies flight and some one is willing to sell them that for less than the price of a private jet I guess maybe there’s potential there? Depends though… just avoiding planes does the trick pretty well too after all.
Realistically given how fast we are killing ourselves with this stuff we should probably all fly less kids or no kids, economy be damned too… but that’s unlikely.
Ultimately it just feels to me like some folks and their shitty algos, strewn across the internet like gastric spatter, want to stir a fight between people with and without kids though and to hell with anything else.
Nothing like the pure hell of international air travel to bring that out in folks.
