Everything's certified in the automotive world too, you know. Red tape abounds there too!
...and they have diagnostics systems you LAME's can't even imagine
...and they sell millions of units a year.
How many million aircraft are sold each year, there in lies the problem with amortising design and certification costs.
The OEM market may survive but I don't see the retro fit market taking off, it'll cost more than most aircraft are worth.
The only reason we had electronic GA EFIS was the development of stability systems in motor cars which paved the way for the "gyro" systems in the EFIS screens to be built at economic prices. But for the systems to get market share they still have to be priced competitively with existing gear and provide extra functionality, which of course they do in spades. Just to get some idea of the cost of certification compare the price of EFIS units for the home built market to the certified GA aircraft market.
Unfortunately a diesel engine doesn't provide a major step ahead for most owners to bother with the cost. Plus unlike an EFIS system which will pretty much fit straight into the existing panel for most aircraft, with a diesel engine there's the changes to the engine mount and probably fuel system and quite likely new cowls and prop etc. Not insignificant items. All to do what?