My 2014 is just shy of 40,000 miles, and I've had it serviced once; at the 26,000 mile valve clearance check. That task was beyond my comfort level. It won't go back again until the next valve check, unless something breaks that I can't fix. Everything else (brake system flush, tire changes, clutch fluid flush, rear differential service, fork service, oil changes, etc) I've done myself. I bought a service manual, but I honestly think you could get by doing all the services I mentioned just from information I've found on this forum. The threads on things like wheel removal and fork maintenance are actually better written and easier to follow than the sections of the service manual.
If I had unlimited funds and boundless faith in the mechanics at whatever shop I used, I'd probably never touch my bike except to ride it. Neither of those conditions exist, though, so circumstances force me to become familiar enough with wrenching to do my own maintenance.
I wouldn't look down on anyone that did take their bike in to a shop for a 600 mile service if they have the money and lack the time/desire/skillset to do it themselves. I do seriously question shops that charge 300 plus dollars for a service that is basically just an oil and filter change. 3 hours?? To change the oil and filter and (maybe) check the torque settings on some bolts? And I say "maybe" because I seriously wonder how much of that actually gets done during a 600 mile service. If you deliberately loosened the rear axle nut, or one of the caliper bolts, and took it in for a 600 mile service, I wonder how many shops would actually catch it? And if any dealership tries to insinuate (or directly states) that your warranty might not be honored if you don't get your bike serviced by them, move that dealership in your mind over to the "unethical crook" category, and take that into account if you decide to use them for any work in the future.