Once your car is older/out of warranty, yes. New cars under warranty pretty much go to the dealer.
Dealers actually don't know much about their older cars. Try to bring for example a 1990's era (or really anything more than 10 years old or so) Mercedes to a dealer for service, none of their techs have any idea what it is, unless they happen to have an old guy.
Dealership shops are trained and reasonably competent working on newer stuff that's under warranty coverage. Older than that, you can often get better workmanship and cheaper prices with an independent.
I never go to the local guy. My dad did, but he loved old cars more than I do. And the one time I did go to his guy, I was astonished at how much he charged. Made the dealer seem downright competitive. And the dealer definitely has better access to parts and model-specific knowledge.
Yea, I was always a "never get your car serviced at the stealership" snob, until I moved homes. Now I'm in a different city and I haven't found a trustable mechanic yet, so for things I can't repair myself, I'm going to bring it to the dealership.
Yup, I had a guy over tighten a spark plug and totally ruin my engine. Had to have the master cylinder repair then it finally crapped out... just to save some dough.
Tesla has service issues, I'm not sure that they're related to their lack of dealerships though.