In case OP or anyone else is curious, I will explain how MMR variance occurs.
It is not some magic lever in the sky that big daddy blizzard is actively pulling and controlling; it’s almost entirely hands-off (although can be adjusted remotely).
The single most impactful cause of “inflation” is, has always been, and will always be player participation.
For an analogy to picture this (not responsible for clean up), I want you to fill up a glass of water and dump it out on a hard surface. Measure the spread, or area.
Now, fill up a gallon jug with water and do the same thing. If done correctly, I’m sure that you’ll notice the gallon jug poured out has a significantly larger spread. If you were to do this 10000 times, the average of the gallon jug area would be SIGNIFICANTLY higher than that of the cup of water (unless you have some super weird cups).
This is how mmr range and inflation works. At the start of the expansion, there are always WAY more people playing than any other season. People always come in and try something new and exciting and rarely see it through in MMOs nowadays. However, even if they quit after a week, a month, or six, they have still added their data to the sample pool if theyve played their placement games at all, and increased the range and caused inflation.
Now realistically, no one player is forcing inflation by themselves by playing on 10 alts, not even bigdam and his squadron of shaman or petkick and his division of DKs. However, when you have anywhere between 2 and 10x the population because a new season/expansion is exciting, it’s easy to see how mmr rapidly inflates.
The genuine truth of the matter is that if every single wow player was to read a post on wowhead or reddit and Q up 20 games or so tomorrow and play a couple games a week, you’d see literally hundreds of points of inflation, if not over a thousand, between now and the end of the season.