The reason being, Scandi Europe has a real hardcore target shooting association, and 6.5x55 was the standard cartridge until the early 80's when they switched over to 308, they could only shoot factory ammo in competition then, probably the same now, I dunno, not up to date on my Scandi target shooting these days.
Eventually the 6.5x47 Lapua came about, and is still the 6.5 target cartridge to beat.
The CM stuff was born and raised to sell guns and ammo to north Americans, North Americans are not marksman like the Scandinavians, different worlds all together.
Be that as it may, it doesn't invalidate that there's an awful lot of very accurate 6.5 CM rifles and ammo out there, and the rifles are throated and twisted to play well with that ammo.
There's a lot of accurate rifles and ammo available in a lot of chamberings, I know.
But lets not say there aren't people who like as much accuracy as the Scandinavians do running 6.5 CM and that its a pretty easy cartridge/rifle combo to get shooting well. Joe Sixpack might not be looking to punch those groups but that doesn't mean people aren't expecting - and getting - more.
Lapua components are for damn sure exellent though!