There are different approaches to learning. Some parents are willing to pay for private lessons or enroll their kids in a music program. A week ago I was at a gathering. 2 high school kids (one plays violin & the other piano). Both are in a music program and playing with a small ensemble. They went through the ABRSM music exams up to a Gr. 6 level. Practicing and taking the kids to their music teachers every week is time-consuming. They played a few Classical pieces for us and ended with 1 Jazz piece.
2 years ago I met a retired man in his 70s. The only thing he wanted was to learn 1 piece his father played many years ago. His father had a degree in music but don't think he had much playing experience. Got an old piano from a friend who moved. Took him 4 months to learn 1 piece with YouTube video demos (imitating finger positions) slightly under tempo. Without getting into basic techniques (legato, staccato, etc.), reading music & foot pedaling he's happy learning just 1 piece.
The cost of getting into any music program (including the ones online) or with a private teacher adds up overtime. There is a basic fee for each lesson. Some parents are willing to pay for the expenses for their kids to get ahead. I'm an adult learner and decided take a slightly different route. The past 5 years I've been with an adult group through the local conservatory who play for interest. We have the choice of taking music exams but none of the people in the group is heading in that direction. We pay a small fee (half as much as private lessons or a F/T music program) for the Fall session (Sep - Dec) and the Winter session (Jan - Apr). We learn a few easy Classical and Jazz arrangements. Since March, classes are held once a week through Zoom while the conservatory is in lockdown indefinitely.
Once you learned to read, you have a whole library that is accessible (online and printed copies). A lot of learning can be done on your own. I download a lot of intermediate pieces outside my weekly lessons. Eventually you may get to a point when getting a teacher is the way to learn more advanced pieces. There are people who learned from easy method books like the Alfred's or Faber series for a few years before getting a teacher. And then there is the self-taught apps like Flowkey, Simply Piano, Piano Marvel, Playground Sessions. I don't have any experience with these so can't make a recommendation.