Why is it that there there is such a mismatch between advanced Permit aircraft who aren't on Part M rules and ancient types (sometimes identical types) who are being screwed by massive cost.
The system has grown up by evolution rather than design. The C of A regime derives from ICAO conventions and standards designed for civil air transport. When ICAO was formed flying was more problematic and machinery less well built and reliable. For that reason every bit of a certified aircraft had (and has) to have a paper trail which shows it is to an standard. The fact that often the uncertified component is the certified one without the paper trail is just one of the absurdities.
The evolution of light aircraft from a regulatory perspective is complex, but for various reasons the high level of regulation in the certified market with the associated high cost of modification or development of a certified design has resulted in a GA fleet which is several decades technologically behind the motor car industry.
On the other hand, permit aircraft which were once all home built from plans have evolved hugely and benefited from the general development in materials, design, electronics, precision engineering etc. Light touch regulation in most countries that have a permit system means that such aircraft can benefit from all the advances we all benefit from in every other sphere. General increased reliability of things mechanical and electronic means that we now have permit aircraft every bit as reliable as their certified brethren (witness the recent lifting of restrictions on permit aircraft overflying built up areas). The irony is that not only are C of A aircraft no safer but they are often noisier (the cost of modifications to silencers being too great to justify it) and less environmentally friendly, generally burning more fuel and leaded avgas as opposed to mogas or jet A1.
The relatively few innovators in the field of mainstream certified aircraft - largely Cirrus and Diamond - speaks for itself. Piper have seen the light with their tie up to market the Sportcruiser.
I would say that the market for second hand certified aircraft is largely dead and likely to remain so unless their is a significant reduction in EASA maintenance requirements, which seems unlikely. Even then many aircraft, the high performance ones, are a dead end because of the disappearance of avgas over the next five to ten years and the expensive conversion work they will require to run on any substitute fuel that may appear.
You only have to look at the recurrent adverts in the flying magazines for some aircraft which have been for sale for literally years. Private single ownership is an option for very few who have specific requirements. The market for group purchase is not great either. Eventually no doubt the second hand market will sink to a level to make it attractive, but it has some way to go before that point is reached. Owners will have to reconcile themselves to taking a big hit on their pride and joy in order to sell!