Looking at these two screenshots, if OS X still looked like Tiger today, I'd expect a cheesy wannabe-lookalike theme for e.g. GNOME/KDE to look like BS. But then, I said the same about Yosemite's design back in 2014 compared to e.g. Snow Leopard.
When the switch away from LucidaGrande and toward (new) SanFrancisco occurred, my eyes and my brain could not adjust to it, just as my eyes have struggled with Tags dots and not Labels bars. What made LucidaGrande and Label bars across the file info useful for not only new-to-Apple users, but also for casual users and power users, was their legibility and comprehensibility.
San Francisco, modelled heavily after Helvetica (both being Neo-Grotesque typefaces), may
logically seem legible to the eyes, and
in the right context, it can be. I’d not find it surprising to learn Apple’s UX/UI team turned to case studies on MTS in New York City adopting Helvetica in the 1970s for its wayfinding signage (or U.S. federal agencies adopting Helvetica for signage, liveries, and stationery).
On
a printed medium, a grotesque typeface is easy to read and easy on the eyes. It‘s arguably better suited to larger text treatments and not body text — “book’-modified variants notwithstanding. This, however, does not translate well to pixels — not even Retina-grade pixels.
Lucida Grande, by contrast, was created and optimized for on-screen pixel display (it’s also in a family of typefaces called
Humanist, which departs from
Grotesque/Neo-Grotesque typefaces along a mess of technical subtleties which are worth exploring if you’re interested in typographic theory). I gather Apple chose Lucida Grande over Chicago (the classic Mac OS typeface) not only because it gave a fresh face for a fundamentally different operating system, but also was qualitatively better for the new demands of on-screen display (heading away from CRTs and toward LCDs) and improved dot-pitch of newer displays.
When something works, don’t break it. It’s an idea Apple would have done well to reflect on when they were considering major UX changes as part of incremental OS updates (and whether those changes were prone to push away power users and limited-sight users who need to scope a display quickly and with an absolute minimum of
conscious cognitive distractions — that is, any UI/UX element or function which forces one to momentarily pause their train of thought in order to execute an action
on that UI). A similar case argument could be made for preservation of well-tested skeuromorphic elements which persisted over several versions of the big cat OS X builds.
In the end, I used
that tiny utility to flip the UI back to a LucidaGrande UX, and to this day I still struggle with the Tags dots on my High Sierra and Sierra boxes. I will not be moving up to Catalina or Big Sur (which, for the person earlier who wasn’t sure what all the post-big cat names are, they’re geographic locations within the state of California, including on or just off the coast — Mavericks and Big Sur, respectively).