If you believe this to be the case, then play more at the start of the season?
My opinion is that rating decay is an extremely negative experience. Rating decay disadvantages anyone who isn't focusing solely on a single game (since they'd have to keep up with all games they're competing in). It disadvantages anyone who does not have the time to continually play games. Without decay, someone who might just have holidays free has a chance to be competitive in the season, which I think is nice. Rating decay also just feels bad.
To me, the idea of a champion for a game is the person who is most consistent in winning. If they do that by beating the best players consistently in the 2 weeks at the start, then that seems fair (at the start they also have the disadvantage that everyone they're playing agains is low ELO). No matter what, you have to play and win quite a few games to get to the top ranking in a season, I don't think it's necessary to decay ratings to make people play more.
The counterpart is that scores might stagnate at times, but I think the season reset is a reasonable solve for that. I saw that there was some stagnation at the end for the games I competed in, but there were still top players playing within the last few weeks of the tournament. I don't know if 7 wonders was just different, but there is still incentive for top players to try to pass each other at the end.
Overall, there are pros and cons to these different approaches. To me, the cons of rating decay outweigh the pros.