I am not a lawyer but would speculate that the issues might be centred on
Most interesting part is the statement that the rates include shipping and handling. While the Avidyne prices are close to that ($1200 for an IFD540), I’m almost certain that they do not include S&H and the units need to go back to the US, which adds another $500 or so each way. Even if only one-way S&H is not covered, that would make the Avidyne pricing about 50% higher than Garmin.
Unfortunately these very high repair prices are just accelerating the rate at which certified GA becomes yet more unaffordable. I wouldn’t take an aircraft with the G1000 in its type certificate even if you gave it me for free at this point.
I did make the point a long time ago that when I travel to some far away places (e.g. Greece) that, of the planes I see down there from say N Europe, relatively very few of them have glass cockpits. My theory on this was that the owners are too nervous to do it in case something packs up and there is not a Garmin etc dealer anywhere, and getting one down there would be a hugely pricey exercise.
However it could also be there is a correlation between “working planes” and owners who don’t spend big money on eye candy and spend it on avgas instead. The modern planes I have seen back home were used mostly for short trips, maybe N France.
As was written here somewhere recently, the G500/G1000 cannot be worked on without a Garmin dealer because you need the special SD card with some “keys” (I have no idea what is on it). However the Avidyne IFD boxes don’t need a dealer; the config is accessible so a smart aircraft owner could do a field swap.
This is a feeling I am familiar with. My plane was apparently built out of a pile of avionics boxes which had been returned to the factory with intermittent issues and the first year was spent replacing these under warranty as they packed up. One day I will meet the TB20/21 GT owner who got my old ones 
I didn’t do any trips for those 12 months.
However, this ripoff move by Honeywell/Bendix-King may well change things, because you will be looking at fixed price repairs of common old avionics in the same arena as a G500/G1000/etc. It is going to be really interesting what this does in Europe because while small shops can still repair these instruments, Euro-reg planes can’t officially use them without an EASA-1 form.
