I've also run Linux on the desktop for over 20 years. Knowing everything in the system is probably nearly impossible unless you're a professional sysadm, like people who specialize in what's called devops now. I agree; I don't want to memorize systemd commands or configure WiFi from the command line; there's convenient GUI tools for things now and it's easy to just work on other things. Even as a developer in a Linux-only environment, I let the devops/infrastructure people deal with most problems if I have them, though of course the corporate computing environment is a lot more complex than my home setup.
I disagree about cars though. Back when I had a car, I did my own work, because it took less time and would be done properly. Unless you have a chauffeur or something (or take Uber I guess, but that costs more money), it takes a lot of time to have someone else service your car: you have to drive it to the shop, then sit there for a while until they can get to it, then sit there while they do the work, then sit around a while longer until they can finally check you out (while also trying to upsell you a bunch of crap), then drive home. Then you find out later they messed something up, got grease on your carpet, etc. Even if they fix that, that's even more time you have to spend. It was a lot easier for me to just do it myself. Someone will probably say something about "loaners" here, but that's usually for larger jobs, not just oil changes.
I disagree about cars though. Back when I had a car, I did my own work, because it took less time and would be done properly. Unless you have a chauffeur or something (or take Uber I guess, but that costs more money), it takes a lot of time to have someone else service your car: you have to drive it to the shop, then sit there for a while until they can get to it, then sit there while they do the work, then sit around a while longer until they can finally check you out (while also trying to upsell you a bunch of crap), then drive home. Then you find out later they messed something up, got grease on your carpet, etc. Even if they fix that, that's even more time you have to spend. It was a lot easier for me to just do it myself. Someone will probably say something about "loaners" here, but that's usually for larger jobs, not just oil changes.