It is much more far ranging than protecting the quarterback, reducing violent tackling, or the guardian cap. The real change is that football, has become a big money business and not a sport, but this is true of most international sports as well.
In the US however, the NFL and AFL always drew on talent developed by college teams. We have seen student athletes wanting to unionize and get paid. If you look at the NCAA rules on “student athletics” you have to laugh, that these college players are often not students and often professional athletes supported financially with big money.
College football is a farm team for professional football. Just look at what happened to the PAC-12 as it disbanded over money.
Via NIL, college athletes are getting paid so handsomely that some are delaying their progression to the “professional” ranks.