Dude you realize that having graph that YOU made means nothing. You post no sources, no idea where your data came from. No idea where your “ELO” comes from or how you’re ranking them.
Why is it that you suddenly decided that you know who’s more skilled or not?
Again, the same graph can be made by simply graphing a random selection of players from Aligulac’s active player list. This is every active pro player in this graph:
https://i.imgur.com/yXkHwZO.png
Do you see the divergence of the yellow and green lines? This is REALLY simple, bourne. You CAN understand this.
Dude who are you rating them against? And why are you supposing that MMR doesn’t just work? And why are you supposing that Zerg just “has” more MMR (and by a wide margin) with no other information other than they have it, and supposing that means they’re more skilled?
The way the Elo/Glicko algorithm works is that their rating as a player is adjusted based on the rating of their opponent and whether they won or lost. This is repeated through their match history in chronological order. It is extremely accurate at measuring skill. The ladder uses a similar system.
When skill is equal, Terrans have anywhere from a 52-61% win-rate vs zerg because the imbalance scales with skill. Terrans get a flat +15.3 Elo vs Zerg and then a bonus 8% on top of that. So at low levels it’s a 2% increase and at Code S levels it’s an 11% increase.
It doesn’t, ever. Somebody with an unusually good matchup has a corresponding unusually bad matchup to balance the winrates, because then theyre facing, in this example, protoss players far above their skill levels, and the MMR balances back down.