My theory is twofold (and I am sure there is more to it):
1. Unfortunately, delayed gratification is an antiquated notion, especially in stark contrast to the immediacy of "now."
2. Parents have become enablers and are part of a player's entourage. To be fair, they've invested lots of time, energy and monies into their kids' athletic exploits. Plus, they love them, which makes for at potentially toxic cocktail. The parent's self worth is so tied to the success of their sons or daughters that they cannot help themselves from imparting their views and (often flawed) solutions on their kids one last time before they become "real" adults.
As a parent with three kids (aged 7-14), all of whom are decently athletic, I too have to fight the urge to speak up on behalf of my kids if I feel things are not happening as they "should." And of course, there are times or scenarios where a parent's or parents' input is absolutely warranted.
But when you reach high school, and especially college, I think it is time to step back and channel your wisdom toward helping your kids navigate and emerge from adversity or disappointment for him or herself. In the long run, that is much more beneficial than blaming a head coach or running to the transfer portal and fishing for a better situation that in all likelihood will not produce discernibly better on-court/on-field results. Additionally, most often, the student-athlete acquires a degree from an institution inferior to that of their initial school, or for our purposes on this site, Syracuse University.