"Lollipop hasn't had that many updates, because it doesn't need it."
On that point I disagree with you. To me Google realizes Lollipoop is a failure and that's why M is attempting to address the shortcomings.
Remember, it's not my opinion, it's my experience w/ Lollipoop & what Google themselves have now stated.
You had a good experience w/ Lollipoop I didn't. Google removed basic OS functionality & I flat out don't like the large notifications. I eagerly look forward to M I hope as I'm certain Google is as capable of botching M as they did Lollipoop. Given all Google's hoopla in advance of the Lollipoop release including better battery life I will always say it was complete failure. Now Google says battery life was decreased in Lollipoop so it's far from just my experience/phone. I'll live with Lollipoop until the 5.1 release & if I continue to have issues roll back to Kit Kat 4.4.4. I'd rather spend more time rolling back to Kit Kat & knowing all my issues will be resolved than factory resetting Lollipoop and hoping they'll be resolved and still having an OS I don't like.