[0] https://github.com/grassmunk/Chicago95 [1] https://garudalinux.org/editions (screenshots don't do it justice)
I can speak to this personally. I used to always tinker with various Linux desktops, themes, etc but nowadays I just use vanilla Ubuntu with zero theming modifications. There are two reasons for this:
1. Like others have said, theming is easy but consistency is hard. I've found that anything besides Gnome just turns into a shitshow where half your apps just don't theme properly.
2. It's a massive time sink. While I could create a very consistent theme, it would involve a massive time sink into dealing with all the edge cases. When I was in college and just used Linux "recreationally", I could justify spending a ton of time tinkering with my system and getting everything perfect. But these days I use Linux professionally so it's less about having a beautiful desktop and more about something that just works and gets out of my way so I can get my actual work done.
I should note that I still play around with other DE's and themes though I now do it all in VM's. I'm slowly building up my own theme stack on a Debian VM and once I get everything buckled up I might actually deploy and it use it on my primary machine.