Original comment follows:
In my view, this would just DRM-ize everything on the web. Of course, Cloudflare and Fastly don't talk about this much, and Cloudflare keeps assuring you'll still get captchas if device attestation fails or is unsupported. But realistically, once all Microsoft, Google and Apple implement it in their devices, there isn't much of a reason to keep accepting non-attested devices. You can already see where this is starting to go - if you're using Linux/BSD or another niche OS, congratulations, you can't submit forms any more. And since device verification would become extremely cheap to perform this way, you'd also see websites protected entirely by this tech, effectively locking out Linux/BSD users. The Cloudflare article also talks about how, at least in the case of Apple, they'd run something like a posture assessment to confirm that your device components are genuine. I can also see this new tech locking out users of non-OEM repairs. This is a much bigger deal than what it seems like on the surface, and I'm genuinely scared about how this one simple move dwarfs all of the "evil" things that big tech has done so far.
...and if you are someone who actually works on this stuff for a living, perhaps you should reconsider and think about what your work is driving society towards. This isn't just the "keeping users addicted" work that often gets discussed here on HN; it's far far worse.
Apple and Google charging 30% for all business instructions running on their hardware and being 99% of the market is also unfree. (No, Google's unfriendly process and scare tactics around APKs do not make that platform open and broadly accessible.)
Maybe Google, gateway to the entire web, shouldn't be allowed to make a browser and set the rules in a way that favors itself at the expense of the rest of us.
Computing shouldn't be a set of four or five companies that control the entire platform and have everyone else beholden to their rules and taxation. We need to make these giants smaller and remove their grip on computing so that competition can flourish.
Every startup founder and free software advocate should want this. Everyone protective of their privacy should worry that in the future only Big Brother signed (and tracked) browsers will work.
We're experts and have a say in how our industry functions. Call your representatives and teach them about this problem. Tell them how it's going to cause everything to stagnate and suck and prevent new businesses from arising.
Also, vote. Big Tech has grown enough power to be a government itself, but not one we voted for. Hopefully the ones we can vote for, can at least restrain some of that power.