Why is the number of supports suddenly such a huge issue?

Title. We got through all of last season with autofill very rarely enabled, primarily for people in very high rankings (and basically never in normals?) - how come this season starting has suddenly caused support numbers to fall off a cliff? Are less people playing overall, or what? The pre-season has been quite kind to supports what with several new support items coming out so I don't know why the community would have suddenly decided to abandon the role - does everyone want to play assassins right now?

What do you guys think? I'm lost.