I don't doubt that Chrome has a lower (real or, even moreso, measured) CTR, I just doubt that its particularly because Chrome users are more tech savvy.

Tech savvy isn't the only explanation for CTR differences, especially measured CTR difference; ISTR a while ago discussions of what was possible in Chrome v. Firefox for adblocking, and from that it seemed that Chrome ad blockers would still download (but not show) ads, while Firefox wouldn't download them. Don't know if that understanding was accurate or if it is still the case, but that could conceivably result in Chrome impressions being overstated (and CTR being understated) relative to Firefox.

I don't doubt that Chrome has a lower CTR, I just doubt that its particularly because Chrome users are more tech savvy.