I ride a few thousand tkm each year with a 1x9. Currently with a 12-36 cassette and 39 t chain ring, hard to ring a more pragmatic and effective set up for commuting or utility riding.
Bingo -- it's not just "why not leave the other chainring(s) on there" -- it's more useful to not have to trim! Many people have no need for so many gears. Bike companies are now outfitting urban bikes with 1 X 8 derailleur set-ups....go to a LBS and see.
I've never understood the concern with dropping chains. I mean, it's not like the FD is staring down the chain and
frightening it from coming off the chainring when it's there or something. If you chainline is good, it shouldn't drop any more than it does with the FD there. If you need a FD or guide to constantly *hit the chain and keep it on you have other problems with your chainline.
I run a 1 X 7 drive and love it.
Never have I dropped the chain. (38 X 12-34t)