Damn, this conversation didn't stay casual.
But, in fairness, your post text was pretty aggressive for a casual conversation.
But, as people have already said, there ain't no such because nobody is/was willing to pony up often enough.
Besides, airplanes aren't sleeping berths. That part of your premise is flawed. It's okay to sleep on flights, but it isn't part of the package. There's no laying down, and no promise made that any flight will be quiet enough for any given individual to sleep, babies and kids or not.
Your expectations of flying being geared towards sleep just aren't realistic. It never has been, barring very limited occasions here and there.
Tbh, you can't even have a realistic expectation of adults being quiet enough for everyone's sleep needs, even if everyone was trying to sleep. Snoring, farting, groans and creaks. Someone would be unable to sleep.
Babies in particular are really hard to ignore for sure, their cries are supposedly evolved to alarm adults into action. Even small kids crying and screaming can cut through a lot. But that's life. Mass transit always has a risk of that kind of event because even the most stable and comfortable vehicles can't guarantee a child won't be bothered enough for occasional fits.
There's no current airlines offering such, not that a quick search could find (and I don't doubt you had already done so). So you're just as screwed as anyone on a bus, train, or a family road trip.
If you want advice on ways to filter out baby screams, let me know. I've done enough time around sick infants to have sorta found ways to avoid being upset by it, which means I can half doze through short crying spells. It's all about riding the response it causes and letting it go while doing some meditation and breath control. Mix in a little self-programming under a controlled setting, and you can eventually mostly tune it out.
