Several co's still use S.P. Not because it is the best linkage around, but because it is simple, easy to maintain and cheap to produce.
Begin knowledge laydown>
Companies like commencal, orange, morewood, trek, etc. use S.P. linkages on a lot of bikes. They are simple, feel good, and are cheap. Thus, consumers buy their bikes. The profits from said bike sales go to producing more bikes, engineering/R&D, and marketing. Now, since these companies sell lots of bikes (for the above reasons) they have more expendable income to spend on marketing. Which means they can hire good Marketing specialists. Who all agree that if a pro wins on you bike, it makes the average person more likely to buy said bike. So, turning once again to massive droves of expendable income, a company will HIRE a pro rider to ride for them, the better the rider, the more they get paid.
And here we have the quandary which most people seem unable to overcome. Pro riders do not CHOOSE the bikes they ride because they are the best, but are PAID to ride the bikes by the companies with the most money. A fast rider on a shitty bike will still go faster than a slow rider on a good one.
So yes, many race are won on S.P. bikes. However, now you can see my reasoning for why these bikes are not necessarily the best.
end rant>
I rode Single pivot for years... Yeti AS-X. It was great, and fast. But it is not the best linkage around. Sorry.

 "the best linkage around" is a very subjective opinion. A rider could be very fast riding a single pivot bike because they are used to the predictable nature of single pivot suspension systems; however on the flip side another rider might perform better on an VPP suspension bike because they prefer a suspension system that handles the unpredictability of various courses. A bike doesn't have to be complicated to be fast. At the end of the day it's still more about the rider than the bike.

This information brought to you by a guy who has owned and ridden 3 VPPs, 3 FSRs, 3 single pivots, and two DW Links.

 It is... but I still see a very simple linkage at the end of the day... Perhaps I shouldn't be so quick to judge, but I wasn't blown away when looking at it up close...

 It's all about geo man. Plow bikes are overrated. Simplicity is where it's at.

 Touche...

 Now I have yet to give one a test ride, but from what I have heard the Morewoods have DIALED geo. That's also a pro paintjob, they usually just have solid colours on the production models.

 ive ridden two mitch delfs old one and a stock one they ride so sweeet , speeeed is key