Tomo, the 30 mm had a whole bunch of problems. First, it could be used only as an inline engine mounted gun on single engine fighters - the reasons can be seen in many other threads on this site. Second, if you put it in the wings, the tremendous recoil would warp the wings and cause not only instability but inaccuracy of fire.
As pointed out by koolkity, MK-108's recoil was easily manageable by 190's wings
And the 109 was too physically small to take the 603.
I've talked about the 190, not 109
Regarding superchargers, every country was going flat out to build the best. Britain and Rolls Royce just happened to be better.
If we take a look into deployment of BMW 801, there is a 3 (three) year gap between 'plain' (under 1700HP) and 801-TJ (1900HP, plus no high altitude problems). And 3 years in WWII is a lots of time.
About RR G.Britain: care to elaborate?
As for 30mm cannons in wings: was there really much of a problem regarding the mounting in FW-190?