They get paid as much as they can get that management is willing to pay for them. They get more now because the teams get all sorts of advertising money.
I think players today are better now than players from years ago. The training and coaching is much better. Also, they are much stronger and acrobatic than before. Weight training used to be disparaged as making one "muscle-bound". Now it is part of the training regime. Today's players are stronger, faster, and more skilled than those of years ago.