Hey, so, I'm the guy who actually took your advice, the last time macOS had a visual change. Yosemite and newer look ugly, so I'm running Mavericks instead! (My case is a little different because I did upgrade at first, but downgraded back after many years because I couldn't take it anymore.)
And the good news is, you're right! I am running Mavericks, and I'm making it work, and on the whole I'm very happy with my computer right now. But, like, it's really hard sometimes!
Every time a coworker wants to do a Slack video call, I need to fire up VMWare Fusion and take the call inside my VM, because Slack video calls absolutely refuse to work in Mavericks. I have spent many hours tracking down Mavericks-compatible versions of apps that aren't sold anymore, or just aren't available for download. I spent days fixing the weather dashboard widget, largely because I legitimately prefer the dashboard, but also because under Mavericks, there's no Today View widget I can use instead.
If you too want to run a very old version of OS X, hit me up and I'll give you some tips. But I don't think most people are as crazy as I am, and they don't really have a choice about whether to upgrade. They can hold out for a few years, sure, but the clock is ticking.
I assume many of the people who spend $1,000+ on Macs do so at least in part because they like the visual design. Having Apple come in and change the product out from under you isn't a great feeling. Users certainly have a right to complain, at minimum.
i care about what's happening under-the-hood more than what icons look like, and love staying on top of 'new'; so, just waiting for the public beta. i genuinely don't understand the point of holding back so far... and having to find workarounds for everything. but whatever makes you (or anyone) happy 👍