Nikon repair service.
Glad I retired when I did (6 years ago after 30 + years as a small shop repairman)
So I was into the digital era from the D1 to the D200, D70, D100 etc.
Nikon is right in one respect, there are some repairs that the small shop or home tinkers can't do. Its not that we aren't smart enough, its because the necessary adjustment software and service info is not available except to the favored "Authorized" shops.
Or if it is available, it is so over priced it might as well not be for sale.
To become an "Authorized" shop is VERY expensive in terms of the mandatory training and equipment you have to buy. Much of which is never used by the shop.
Many years ago, when Mamiya was distributed by B&H, they tried the same thing. It didn't go well for them and after a year of so started to sell parts again.
While, I couldn't do a complete recalibration of an autofocus system for example, there were many repairs to digital cameras and lenses the I could do as well as the big boys and had many pro customers that could get their stuff in a day or two, instead of weeks.
When flash feet were plastic, the local newspaper fellows would get them while they waited.
Unlike the auto repair people, the trade groups representing repairmen are very small and with very shallow pockets in what is clearly a restraint of trade issue.