Why Can’t Modern Football Players Act?

So someone help me out here: why don’t modern football players transition to acting careers as successfully as old timey football players did?

In the Olden Days, we have:

In the modern era, we have, what? Brett Favre in There’s Something About Mary? Brian Bosworth in Stone Cold?

Take a look at this list: 50 Football Players Who Acted in Movies and note that the ones who could be said to have made a successful transition to films and television played prior to the 1980s, and that most of the roles from then on are as “Self”? Is it a transition in football culture? Is it that older players were better-rounded and most professionals these days are football robots, funnelling all their energy into it from an early age?