I don't think I've ever met anyone who actively taught their child to walk. I mean, I can see how it could be necessary to intervene for kids with disabilities that affect walking, but kids generally just get up and walk when they are ready.
I do think that in all this talk about sleep training, the parents who sleep train say that it was great and their children sleep really well and the ones who don't say that their children would be traumatized but it, and I think that in the vast majority of cases, both sets of parents are right.
If you are a parent who is in tune with your child and wants the best for them, you will generally try to give them a good sleep environment with good routines and sleep hygiene. For some babies and toddlers, that's enough, and there's no need to go any further. For others to they respond well to the routine, but they need more quiet, or alone time, or are the sort of sleepers where they will respond well to the lack of stimulus of a sleep training routine, and will find those coffees really helpful in going to sleep for three next free years. And some kids really struggle with sleep. Sometimes they are neurodivergent, or have undiagnosed pain or discomfort, or sleep needs that are atypical, or are just a bit behind developmentally when it comes to sleep. And those babies respond really, really badly to sleep training, and it's miserable for all concerned.
And some parents aren't in tune with their kids, and leave their babies to cry alone until they vomit for weeks at a time, or give them no routine or stability and interfere with their natural sleep development, but I suspect that the parents who ask for support on parenting forums, or read up on infant sleep so that they can do the best for their baby generally know their babies well and are pretty competent at interpreting their wants and needs. And they down that path of increasing levels of sleep intervention until they either reach a stage that works for them, or they reach a stage that indicates that slept training is not something that will be positive at this time, for this baby.
So often a child who isn't sleep trained and goes on to struggle with sleep in later years isn't that way because they weren't sleep trained, but rather wasn't sleep trained because sleep is something they struggle with, and they need a longer, slower process than that in order to develop good sleep.