I agree with
@Augenis, but there's also a another factor.
This is a map of the different kind of types of dominant plant growth in Russia. The East Slavs lives in forest areas at the time, and the majority of the population still lives in those areas. Those areas are pig country. Pigs have two niches one is garbage disposal, here they can be replaced with chickens, but the other are getting calories out of forest areas, in a cold climate they can't be replaced with chickens in that niche. So adopting Islam would mean a major calorie loss. Of course some will mention that some Muslim population do eat pigs, but the problem are that there's two kind of pig eating Muslims, one is Muslim which have lived under Christian overlordship, the other are groups of people who have converted to Islam after being conquered by other Muslims. If they convert to Islam, many of the political benefits of converting disappear, if they have to break a so important religious taboo. Just see the reaction of other Muslims to the fact that the Volga Bulgars only prayed 4 times a day. Alcohol is also important in a cold climate, as it enable people to get different vitamins in the winter, but it have less importance, as the taboo against alcohol is much smaller, and many Muslim culture broke it.
So in my view the biggest problem with Russians convert to Islam is that it offer the Russians nothing, and the only way I could see them convert are if the steppe people conquer them and force Islam down over them, but I have a hard time seeing all the Rus being conquered to such a degree, usual the steppe people pillaged and raze some of their cities and forced the Rus to pay tribute, they was never really able to truly rule over the Rus.