[imchillyb]

Mechanics are in business to be profitable.

Specialized items require specialized tools. Specialized tools, like all other tools, require maintenance and they change.

A shop dealing with domestic produced automobiles can significantly reduce profit-bleed by not servicing vehicles that require special tools, special diagnostics, special machines, etc.

It's simply a math equation. Do I serve enough of these vehicles daily/quarterly/yearly to make these expenditures profitable for me? The shops you're referring to answered no to that question.