Revolutions have had a history of dramatically improving living conditions for everyone as soon as the old system is abolished. The Russian revolution ended famine and doubled life expectancy.

Alternatively, there can be the simple recognition that breaking the system that exists will result in a mass casualty event

Revolutions also don't have to result in violence (think of a mass strike across the entire country that never ends). But when capitalism gets desperate it will start a civil war if that is its only hope to maintain the old system.

And think about the mass suffering caused by mass poverty, genocide, minority oppression, political polarisation, endless war, boring work and the list goes on. If one revolution is all it takes to install a democratic society and fix so many of our problems, I know I'm on board.