Some for wages.
Some for a Big Idea, a Cause.
I've known Russians, never emigres, that were committed like that--and to a person they were embittered and often furious at the lack of appreciation and loyalty shown to them by the renegade peoples that left the USSR. From the internal POV, the Russians had done nothing but suffer and sacrifice for others, messiah-like. They forget that losses during WWII were distributed, not just Russian. So Ukraine lost half the population (from military losses, famine/disease, pogroms) as Russia in WWII, but had a far smaller population so the losses were almost twice the percentage of the population. But they dared to not be grateful.
A pundit pointed out that there's nothing more dangerous than a leader who subsumes his country to a Cause. At that point the population is the means to advancing the Cause.
Putin was raised in a Cause. Dedicated to the Cause. It was ambiguous between "building socialism in one country" (Stalin's phrase) and what amounted to a continuation of the tsarist Russian empire. (Russia never decolonized--even Iran lost a lot of its empire and only has bits and pieces of its empire left; unlike the West, which had to face decolonization and losing empire, Russia only barely did in 1991, and that was less of a shedding of peoples and lands that the populace accepted and more something that the populace and most leaders felt was inflicted upon them. China's not much different in that regard.)
Ideologues shouldn't be allowed within an ICBM's distance of power. Ever.