I don't think your assessment/description is completely correct

From https://blog.cloudflare.com/moving-from-recaptcha-to-hcaptcha/

Earlier this year, Google informed us that they were going to begin charging for reCAPTCHA. That is entirely within their right. Cloudflare, given our volume, no doubt imposed significant costs on the reCAPTCHA service, even for Google.

I think they're planning on charging CloudFlare for reCAPTCHA, not everyone

https://developers.google.com/recaptcha/ still says

reCAPTCHA is a free service

I don't see anywhere else they're going to start charging other people; though there is a a slightly different product where they do charge - https://cloud.google.com/recaptcha-enterprise/

I note, this doesn't make the request invalid or anything (the privacy concerns are indeed very correct), just a few things needed clarifying

Change 588051 had a related patch set uploaded (by Reedy; owner: Reedy):
[mediawiki/extensions/ConfirmEdit@master] [WIP] Add hCaptcha

https://gerrit.wikimedia.org/r/588051

Patch above seems to mostly work. Not massively well tested

Change 588051 merged by jenkins-bot:
[mediawiki/extensions/ConfirmEdit@master] Add hCaptcha

https://gerrit.wikimedia.org/r/588051

Change 589653 had a related patch set uploaded (by Reedy; owner: Reedy):
[translatewiki@master] Add ConfirmEdit hCaptcha for translation

https://gerrit.wikimedia.org/r/589653

Change 589653 merged by jenkins-bot:
[translatewiki@master] Add ConfirmEdit hCaptcha for translation

https://gerrit.wikimedia.org/r/589653

Thank you; this was quick!

Change 608080 had a related patch set uploaded (by Reedy; owner: Reedy):
[mediawiki/extensions/ConfirmEdit@REL1_34] Add hCaptcha

https://gerrit.wikimedia.org/r/608080

Change 608080 merged by jenkins-bot:
[mediawiki/extensions/ConfirmEdit@REL1_34] Add hCaptcha

https://gerrit.wikimedia.org/r/608080