What's going on with "auto" lately?

I noticed this at first on my Apple TV didn't think much of it. The TV is kind of far from the wifi - the app automatically sets quality at 320 or 720 when auto is picked.

Today I'm noticing even in Chrome on my desktop sitting next to a PC that's wired to the router at 5 gig - same deal. Auto sets to 720p. What's going on here?