The catch here is that if DFP were to enforce technical standards to the extent of including performance, publishers would leave en masse. What they want from DFP (as I understand it) is hosting that just works; they don't want anyone in the way causing some ad campaigns to not get trafficked at the right time, or killed after serving for a while, or anything else. And worse, I think that you'd find that a very large number of ads wouldn't comply with any such standard - display ads aren't good, by and large. So even with a perfect offering publishers would look at the numbers and say "you know what, nevermind...turn the crappy ads back on." A pretty good approximation for publishers I've found was to say "if you give them a knob between anything and revenue, they'll turn it towards revenue." That by and large includes sacrificing user-first principles.
So one difference to your example is that viewability is desired - it's a direct metric that helps to approximate value, which advertisers like. But performance is not. Users cannot generally tell _which_ ad made their browser lag, or that it wasn't the page's fault. The best you could possibly do is to measure long-term-value, but because any given publisher only gets a tiny fraction of a user's time, and any single ad that much less, my recollection is that the LTV isn't really moved at all regardless of experience. It's going to take an industry-wide shift to move the needle here.
HTTPS is a closer comparison, except that it takes big parties again to force the issue - it's user positive but revenue negative and lots of work. So it comes back to the issue of who can get this change pushed through, without some party (pubs, advertiser, or users) just walking away. Look at examples of where/why HTTPS has been adopted if you want to see more.
AMP may get to that point, we'll see, but I like it as a possibility. And it's doing more to simply not show ads if they're taking too many resources (with browser assistance iirc? Delay loading? Don't recall what I've read), which is good in other ways.
Which reminds me, that's another plausible solution that I'm liking...if browsers can be more involved in aborting rendering bad iframe'd content, or preventing them from janking the page, etc, then the burden is squarely on the advertisers to fix or suffer reduced impact, irrespective of publisher/ad network. That's great, it puts the incentives cleanly where they should be. So I'm also hopeful that browsers can push through positive results here. Doesn't help with content badness (only latency and other such browser-measurable "bad ad" issues), but is a great starting place. (And to be fair, I don't think AMP solves for content badness either).