I fear that it's not just the 0.5um process but Canon generally lacks behind sensor technology.
Canon is simply forced to push their customers to FF because they cannot compete in the APS-C arena (or in general with DSLR bodies with high pixel density=small pixels).
With equal pixel size Canon cannot compete with sensors using more inventive technology...
Defiine 'compete'. Last time I checked, none of the manufacturers you're discussing sell naked sensors to consumers - they all sell cameras. Since Canon sells more cameras than any other dSLR maker, I'd say they're winning the competition.
Canon is in a very comfortable position at the moment (I'd say too comfortable) but can they continue like that with a senor tech. that is getting more and more behind competition?
It has started with Sony sensors (found in many DSLRs like Nikon and Pentax) that have better dynamic range in low ISO than any of the Canons (FF included).
Panasonic is claiming now approx 1 full stop light utilization enhancement. Just imagine that technology appearing in m43 bodies (and please don't tell me that e.g. Olympus E-M5 not selling well).
I personally know people who have switched entirely to m43 (mainly but not exclusively from Canon; sure non pro users) and I myself have started to use m43 along with Canon and I have to tell that I'm very pleased with the results.
The Sony sensor that can be found in latest m43 bodies is it least as good as the latest APS-C Canons (despite the 2/3 stop disadvantage from sensor size) so from the pictures alone it would be hard to tell which system is used.
Thus apart form the slightly shallower DoF/more background blurring I don't see what advantage Canon APS-C has (note: FF is different). OK, maybe ergonomics but again for non pro usage that matters less.
The whole system is lighter and less bulky though, which is a huge advantage for me.
Most of the m43 primes are also very usable already wide open.
So from IQ perspective it's on par with current Canon APS-Cs. Add 1 stop advantage and it will leave Canon APS-C in the dust.
So to me e.g. the m43 is very competitive and brings me huge bulk saving at the price of 2/3 stop less background blur.
Sure it's not for everyone (e.g. long primes are missing so e.g. it's not for birders) but IMHO it very well covers 99% of the needs.
That's competitive enough for me.