Anybody think the Bolsheviks could have been stopped?
By the way, I might do a timeline on this later.
Stolypin wasn't without quite serious opposition both left and right, so his freedom of action politically would still be limited.
That said, if he builds on and intensifies the development of the Stolypin Reforms, there's a good shot that the rural peasantry and free-holding farmers become significantly more prosperous and much less susceptible to left-wing agitation. As it was, the peasantry was fairly loyal to the monarchy until late in its life.
There's an interesting question of the impact on Russian trade and industrialization if agricultural productivity begins to rise quickly enough as well.