"But yeah, upstream Linux kernel development is taking it slow."
Taking it slow seems very appropriate to me. This seems to me to have been a case of everybody grossly overestimating the short-term portion of the catastrophe, and underestimating the long term.
In the short term, the only people who were going to be plausibly affected in the next three to six months are people on shared hosting of some sort where you may share a server with somebody else's untrusted code, where an accelerated fix is in order, but also something that can be centrally handled. I'm not that worried in the next three to six months that my personal desktop is somehow going to be compromised by either Meltdown or Spectre, and personally, if I see a noticeable performance issue I may well revert the fixes (I'm on Linux), because first you have to penetrate my defenses to deliver anything anyhow, then you have to be in a situation where you're not going to just use a root exploit, which probably means you're in a sandbox or something which means it's that much more difficult to figure out how to exploit this. For most users, uses, and systems, spectre and meltdown aren't that immediately pressing.
Meanwhile, in the long term this may require basically redesigning CPUs to a very significant degree; there is no software patch that can fix the underlying issues. It is difficult to overstate the long term impact of this class of bugs. IMHO the real problem from the jousting match with Linus and Intel last week isn't that Intel's patches today aren't quality code, but that it makes me concerned that they're just going to sweep this fundamental problem under the rug. As I said in another post on HN, I fully understand that remediating this is going to be years, and I don't expect Intel to have an answer overnight, or a full solution in their next "tock". But if they're not taking this seriously, we have a very large long-term problem. We're only going to see more leaks in the long term.