I just wrapped up a 10,520 mile perimeter tour of the US. Here's a list of parts replaced during that time to give you an idea.
Brakes - 3 sets. Going through the Adirondacks, Rockies, and Cascades will definitely eat them up, especially 14 mile descents.
Chain - 3 each. All the torque climbing really takes it's toll
Shifter cable - 1. Had issues from the start but glad I had a spare.
Bottom bracket - had to replace in Washington state. Went from a press fit to a Wheels MFG threaded. No issues after that.
If you're doing a lot of climbing, I did 326,000 feet on this tour, it's going to eat your drivetrain a lot faster.

Never had an issue with spokes or wheels. Was running Hunt carbon 650b's that are still as true today as the day they came out of the box. Fantastic wheels at great price.

After - replaced chainring, rear derailleur, bar tape, brakes needed bleeding, tires again, and all bearings repacked. Rear cassette might survive a few hundred more miles.

The secret is to invest in quality parts and components. Things always seem to break or fail the farthest possible distance from help, I got over three hundred goatheads in each tire when I was in the middle of the desert in New Mexico one day, dead in the water 50 miles from help. Know how to replace/repair everything yourself.
Funny thing was my seat broke. Bike tipped and slid down a tree, causing the wing on the right side to snap and fold upward. I run an Infinity seat mainly because I hate wearing padded shorts, always feel like I'm in a diaper and had horrible saddle sores no matter what saddle I used. This one, no padded shorts, no saddle sores, and super comfy. After my seat broke I had no choice but to ride until I could get a new one. I tore a hamstring and rode for 3 1/2 months with it before I finally got my new Infinity in Florida.