Dribbble wrote a post about logo updates and closed with a really elegant line, which I feel applies here:
"The nice thing about refining as opposed to redesigning is that the old and new can easily coexist."
Yeah, there are numerous hamburger incarnations, but that's because they've been rolled out at various times. Thankfully, the system is strong enough to bare these seemingly random variations, and everything still works basically as expected.
They'll tighten up with time, but for the time being, shit ain't half bad.
Interesting point. I think the problem is that they keep rolling out incomplete versions of their design without revisiting the previous releases. I'm sure dribbble will update their logo across the board just like Instagram did. If you change a design pattern on your product, it should be reflected everywhere.
Another problem is that these teams most likely don't work with each other. You probably have one team designing the actual HIG, which doesn't take into account all these use cases. The other teams modify the design to make it work for their product, which is understandable. Unfortunately the end result is inconsistency.
Finally the biggest problem is that there is no gate keeper. No one looked at their catalog of apps and said "we have 11 different variations of the same menu. Let's combine them." I'm sure dribbble will use the new logo moving forward. Judging from Google's previous design decision, I doubt the inconstancy will stop anytime soon.