If I want to install and use a different desktop environment than came with my distro, what (if any) problems can I expect to encounter?
I’m not knowledgeable about kernel tweaks, but switching DEs is very easy on Debian and should not cause any problems. Just install the desktop metapackage (e.g., “task-kde-desktop”) and you’ll be able to choose it from the login screen.
In addition to reasons already mentioned (phones, big cars, COVID), I wouldn’t be surprised if the aging population was a factor. There are way more old people now then there were in 2010 and that means worse vision and reflexes. Modern cars also offer less visibility which makes it harder to be aware of your surroundings even for good drivers.
We really need slower streets and smaller vehicles as well as public transit. I also don’t like how EVs are marketed largely for being super-fast. They accelerate way too quickly and reckless drivers love flooring it from stop lights