(I don't think the scenario as a whole seems likely, but this specific argument is analogous to e.g. concerns about Uber and Lyft competing with taxies on VC-subsidized pricing that will run out one day, or the loss of SF laundromats thanks to laundry startups.)
Although the Google CA, Google's root trust programme, and the Chrome TLS implementation people are three distinct teams at Google, common sentiment among the technically savvy (which would include all three groups) is that EV is either entirely or largely pointless and nobody cares, so it would not make sense to request EV treatment.
Your general thrust is right, there are other things CAs issue that Let's Encrypt does not, but the numbers still tell a story of solid growth even in the Web PKI, Let's Encrypt grew the market considerably, seizing 75% of a market that is now five times bigger than before doesn't squeeze out other people.
And, if its my job to check that box or to make money for a CA, well, that's fine. But, it terms of them actually having a real use, I'd love for someone to tell me what that real use actually is.
For example: https://twitter.com/musalbas/status/1038919152826757122
Having an EV cert for yourwebsite.com does nothing to prevent fishing if people are directed to someotherwebsite.com.someotherwebsite.com. So, whats the point if going through the extra pain / expense of getting one?
Given that he never noticed it, and the fact that I've never heard of anyone else noticing it. I'd say that even when high-profile targets deploy EV, it still does nothing.
A possible exception might be banks. I've heard (I think in the HN comment thread of [1]) of people actually calling up banks asking why the name isn't in the green part of the browser. I know I check that address most often. I guess people are just most security aware when it comes to mixing the internet and money.
[1] https://www.troyhunt.com/on-the-perceived-value-ev-certs-cas...
These "extra" certificates are sold at a premium 1) so CAs can earn more, despite the race to the bottom; and 2) so potential victim companies of data breaches can point to all the "extra" effort (read: money) they invested in security. But they fundamentally do not improve security, because they're predicated on the idea that non-technical end users will use increasingly more sophisticated methods of identity assurance. The software security industry has decades of case studies which demonstrate this is not the case.
Simply put: you can't solve phishing by stuffing more and more authentication signals into a URL bar and a padlock icon. Approximately all users won't even bother to check and most will simply click through warnings. Trying to design better, more "verified" certificates is a clear example of a local maximum. It seizes upon a weak proxy for security against phishing, then tries to optimize further with the bureaucratic scar tissue of identity verification. In so doing it completely loses focus on the core issue.