It's pretty obvious - they never really thought it through. I don't see how any rational person would otherwise fail to recognize how the current rewards system quite literally discourages players from returning and playing again next season if they want all the different plates.

It's kind of absurd to realize that, if I was wanting the Diamond plates, my best course of action would be to literally not play a single ranked game at all this entire season. I mean, this entire system is basically transplanted directly from Feast with only some minor alterations. Feast was basically dead after the first two or three weeks each season, and people actually pushed rank because they wanted all those sweet FOMO mounts and armor sets. That ain't the case here.

I wouldn't actually be surprised if they change this in 6.2 or later. I sincerely doubt we're the only ones leveraging this complaint. And like I said, any rational person is going to admit that any rewards system that literally discourages you from playing the game is an inherently broken one.