Cars aren't the best comparison.
Doesn't work like that with most consumer items, from cars to TVs though in practice. What happens if you buy in one country and then move to another and have a problem? Or are on holiday? I can just see a Volkswagen dealer in the UK telling someone in that position to crate the car up and get it sent back to the dealer in Germany or wherever it was he bought it.
its very much different in different sectors and with different brands. Your example is of course correct with cars. But equally you wouldn't expect to buy a Playstation from Curry's on-line you wouldn't expect your local games store to sort it out if it broke for free. Its the same with most brands in the bike industry. The warranty system is set up to support the dealers who sell the products. Ie one of my riding buddies has a set of Easton Wheels that have failed. He bought them on-line so he's had to send them back to Wiggle. Had he bought them from the local shop, he'd have paid a bit more, but they'd have helped him out with no need to ship the products back to Wiggle.
Some brands offer world wide warranty coverage and you can just walk into any dealer and they will sort the warranty, but the vast majority in cycling do not. You have to return the faulty product to the point of purchase.
But what if the bike is out of warranty Col? What then? You say take it back to the dealer...? What if dealer only says they only sort things out if under warranty? What if the dealer is far away? What if you want a quote? How do you get stuff like Bosch fixed if there is no warranty left? Are you also saying it is basically not possible to fix a Bosch problem on a KTM bike if out of warranty or if no dealer (for whatever reason.. !)?
If the bike is out of warranty, you just take it to your local shop to get fixed, or indeed you can send it anywhere to have it fixed or repaired. No bike shop should be saying they'll only work on warranty parts... if they did that they'd go bust very very quickly. A high % of any shops income is from servicing and repairs.
If you are dealing with a shop thats a long way away, this is something that I'm afraid was your decision when purchasing. There are many advantages to mail order, but equally if things need fixing or sorting out, there are some big disadvantages.
If your bike is out of warranty, fixing, servicing is 100% possible and can be done by any shop.
I hope thats answered all your questions, if you have any more, please try to make them specific questions so I can answer them clearly.
Regards
Col.