Oh, what I would give for a bit of modern technology that, whilst arguably less robust, can be fixed quickly.
I'm not sure that it can always be. At least with a Tomahawk or Cessna you can probably find parts on a scrapheap somewhere, or buy a new aircraft for £10,000-£15,000. But if Grob take 6 months to supply a spare structural part, you're in trouble.
Also, big name older aircraft tend to be at least supported by somebody. There are so many newer less established types that many of the manufacturers will inevitably go bust, and a dinged wing will mean a trip to the scrapheap whereas with a spamcan or type still in production it would just mean ordering a few new parts.
I don't like it, but I can see why the situation is as it is.