> Why does this article claim that attestation is unlikely?

Facebook is still going to want me on their websites even if I’m running Firefox. Most websites people visit will not do any chrome WEI attestation. Likely exceptions are sites which handle any legal, financial, or health-related data. Not credit cards. I doubt most Google properties will use WEI.

They still want to slurp up all my juicy Firefox usage data and I bet they think a lot of such users will drop their services like a rock if it meant otherwise dropping their browser.