That was more directed at the F-ING SSL issue, but still, end of 2015 to have a feature that's considered standard nowadays and introduced 7 years ago?
How much of the work that went into deprecating certs and removing obscure command line flags and setting up HTTP/2 (which isn't even really used by anyone yet) could have went into electrolysis?
None of it. The work on multiprocess Firefox is primarily an issue in the front end UI code (written in JS), and does not have much to do with networking or crypto.
Another thing to keep in mind is that patch notes are a list of user-facing changes, not a breakdown of where the engineering effort went in a particular 5 week release cycle. Removing the command line flag probably took an engineer an hour or two to do. In the same time frame, I spent weeks analyzing and fixing a variety of leaks that only show up in multiprocess Firefox, but none of that shows up in the patch notes.
SPDY indicator[1] tells me that HTTP/2 is active on all Google properties, including YouTube. That's a nice chunk of the web right there.
I agree with you on older bugs just lingering around. This is a serious issue for many open source projects. JWZ was complaining about it years ago[2]. My favourite example is the problem of putting the tabs at the bottom of the window in gnome-terminal[3], which has been reported over 12 ago, has a patch available posted in the bugzilla, and it's still not fixed.
How much of the work that went into deprecating certs and removing obscure command line flags and setting up HTTP/2 (which isn't even really used by anyone yet) could have went into electrolysis?