When I was a kid I always got my Shabbos shoes from Payless, starting from when I was about seven. They were fine. My family isn’t poor, ch”v, my mom just likes to get deals.
However, I can very easily see why a parent would want better shoes for his/her kids, especially if these are their shoes for the season. If someone is willing to donate the money for the shoes, and the parents decide that this is what they want to spend the money they receive on, then gezunte heit.
I always consider myself lucky that I b”h am fortunate to have everything I need and a very decent amount of what I want :)- I’m not going to make judgments on what other people have or get.