There is an easier explanation: Kremlin just started to spend money on its Internet presence and opposition could not match it, which got amplified by more people getting connected to the Internet (thus instead of tech savvy crowd sympathetic to opposition, you get a bigger share of conservative "simple man"). Opposition just got relaxed and thought that Internet will be their home ground forever. And it's far easier for opposition to blame Google for collusion with the government, than to work hard on quality of their websites. Compare the old "non-systematic opposition" influence with the drive behind people like Navalny and you can see that there is no conspiracy, just laziness vs hard work.