> Personally, I think they may have underestimated (or failed to fully predict) the anti-google, pro-privacy sentiment in the wings, and it's clear even from this thread and the issues on bugzilla that it's probably cost them enough privacy-capital at this stage to have justified the extra work required to self-host.

Or maybe the "anti-google, pro-privacy sentiment" isn't really all that big. Could be a relatively small but vocal set of people.