In my opinion, the fact that nowadays all-in-one UIs are almost
too good has done its part to the "quieter time" of the UI design community. Not that that is bad or anything, I rather have my friends use TukUI than their own bottompanel-stasheverythingthere-notevenviewport-setups
There are all-in-one user interfaces for pretty much everyone's taste, but it's a lot harder to personalize them if you compare them to the old "create your own perfect UI just by picking the best AddOns and WTF files from your favourite UIs" method which works (relatively) effortlessly only with standalone AddOns.
/justmy2cents