[TheCapn]

Perhaps you're using a broad/generic example to try and make the point but I'll say this:

If a seasoned mechanic is unable to figure out how to reset the Maintenance Reminder or look up how to sync Tire Pressure sensors, run away.

In the same way that one can use knowledge of one programming language as a means to leapfrog into other languages, other skilled trades are similar. Perhaps there's something that could be said about an ICE mechanic trying to dabble on Electric but that's not the point you're making. So yeah. I know you're trying to make a point about lock in, but when I think of people I want to hire for tasks who might say "Oh, sorry, you have a Volkswagen and I only know how to work on GMC" I wouldn't take my GMC to them either. It shows a fundamental lack of skill in that they don't understand the broader concepts and their universal applications. If I, a programmer, can figure out my Volkswagen, my GMC, my Mazda, my Nissan, certainly a mechanic can. If my appliance repair specialist can only do Whirlpool when I ask for help on a Bosch that's red flags.

One might specialize. Sure. But to refuse? Weird. But I fear I might be getting lost in the weeds here because its all about the approach. "Sorry, too busy to take on work on things that aren't my specialty": yep, understood. "Sorry, I don't know <model> I only know <other model>" bad.

[hakfoo]

I know mechanics in particular can be quite chauvinistic.

In the US, for a very long time, you had to find an "import specialist" mechanic, even long past the point where Japanese brands had gone mainstream. Part of this might have been because of the availability of metric tools at the time; my family had a set of metric wrenches specifically because they had to do occasional light maintenance on their early Datsuns and Toyotas.

I can recall that the mechanic in my neighbourhood was decidedly unwilling to service a new Hyundai in the late '90s. He complained they were 'disposable'.

[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.

[ozim]

Try to get a French car in Poland, most shops are used to deal with VW, Audi.

It is not impossible but if you try to go to a random shop you found on Google and fix your Citroen or Renault you might be surprised.

[wisty]

It could just be a parts issue. A lot of mechanics will work on pretty much any car, if they have the parts, but if it's not a popular model then they don't want it sitting in their shop for a week while they order parts.

I guess some mechanics will prefer to work with a smaller number of models, because they're much faster if they're familiar with the model, but new models come out every year, and they need to learn how to fix those. If a mechanic can learn to fix the newest VW, they can learn to fix the newest Renault, it just might not be worth their time if they have enough work to do.

[MSFT_Edging]

That's often certain German cars in the US. IE some shops will just not work on modern Minis. Plenty of shops will avoid weird, niche cars.

Any mechanic can fix a Citroen, but is it worth the floor time it'd take to get the parts and figure out french quirks vs working on something they know that they'd make the same money in a third the time.

Having done shade tree work on various cars, I'd totally turn down any Subaru engine bay work if I was already close to swamped.

[MobiusHorizons]

I think you are missing at least one important point. The reason the mechanic can’t work on the other brand of car is not knowledge or skill, but equipment. It costs money to buy the full suite of equipment required to correctly service a particular manufacturer’s vehicles. It often makes much more sense to specialize and make more use of fewer expensive tools than to have tools for everything and have only marginally more business.

[Dah00n]

Well, that's a very American way of doing things that most places simply don't do. The norm is for tools to be compatible with all brands and at best it is an added option to unlock or a pay per use. You can do 99% of the diagnostics with a Wish Bluetooth dongle and a free android app if you wish, since by law it is an open standard.

Most specialty equipment costs less than a mechanic can earn in a day. You even order the parts from the same company no matter if the bumper is for a Mazda, VW, or an Alfa. Or a Kawasaki motorcycle for that matter. This lock-in behavior is, luckily, mostly illegal.