I don't believe the small mechanical difference in click activation actually makes a huge difference to uptake numbers, since the big leap is making the choice

I don't believe the small mechanical difference in click activation actually makes a huge difference to uptake numbers, since the big leap is making the choice to have plugins not run by default, with the activation path making no noticeable difference since by then you've already filtered out most people, who just don't care about plugin activation. This feature is driven by the Chrome security/privacy teams, who would have reverted it by now if they saw a regression in usage.