Don't take it seriously. Who cares. No one will care.
Promotion and relegation is great from a sporting aspect. However, it is horrible from a financial aspect. American sports franchises in the NFL and the NBA are pretty much the most stable in the world. For better or worse that closed system led to that.
Secondly, in American sports like football, baseball, and I'd even argue basketball still can be lumped in at this point. These sports aren't, well football and baseball, globally played sports. There isn't enough quality players to begin with to support promotion and relegation and more teams. It would be such a reduction in quality that promotion and relegation would be awful to these sports. Just because something isn't ran to the way you'd like doesn't make it inferior, wrong, questionable, or whatever.
In fact, these leagues have been ran far better than you would have done with them just by your post. You don't know what you're talking about. Americans don't watch amateur sports, lower levels of professional sports. It's all big markets, big teams and powerhouses.
It's reverts back to the Super league crap. These owners are wrong in that instance. However, the business model and set up is perfect for America.