In general, correct -- the best approach is to look at results
Nothing speaks better, then the fruit of the method.
That is why I am very impressed with Yamaha method, among a few others. But there are so many different schools and approaches out there and what works perfectly for some children might not be a perfect fit for others.
However I would be careful to judge success or failure of a certain method based on the presence of video recitals and success stories on youtube. Overwhelming majority of people would not be going out of their way filming themselves and posting their success or progress videos on the youtube. Unless it is part of their learning process or a condition to participate in the program
So making conclusions based on the amount of video recitals of the students using a certain program would not be correct.
I met lots of amazing young musicians (interestingly, they followed different learning programs as young children or even none at all), but for the most part they dont even have an account with youtube :-) It is not about advertising. They enjoy their gift of music, they improvise, they sing. Some of them play from the sheet music, many - don't. They just hear the music and play it...