You cannot be serious? The two systems share one similarity, and that is they are progression systems. In MLB THE SHOW, I'm not able to rack up points and make an F Potential SS into Derek Jeter. I can tell them what I want them to focus on in practice, which allows me to indirectly mold a player to fit my vision, but I can't just turn him into a godly player by racking up base hits, steals and putouts.
In Madden, as an above poster described, I could take a scrambling QB, rack up rushing yards and rushing TDs, and use the experience from that to make him a better passer. Madden's progression system also doesn't allow for backups to progress. Instead what we end up with is All-NFL starters on every team with terrible depth, except the User whom has players with almost 10k more XP points, meaning he has even better starters as well as better depth.
Now lets view that as a bug, or design flaw and look at the system even more meta. Ratings in Madden equal a players ability. A player does not break out unless they have the ability to do so, or the system around them benefits them more than the previous system. In Madden, we expect guys without the ability to break out, to get better because the user forced them to breakout by constantly feeding their stat line. This is even easier to do because of the lack of drops, terrible coverage, robo-accurate quarterbacks, and lack of fatigue. Meaning bad players can play well above their ratings, which creates a snowball effect where playing above your ratings means your ratings should be higher, which means the user can do even better with the player, leading him to play above his ratings even more, leading to further progression.