Do you really think the provisional government would have just lasted if Lenin had stayed home, so to speak? From where I’m standing it seems someone else from some faction somewhere would have started their own coup.

The previous coup attempt against the provisional government failed because there was no mass appetite in the population for a coup from the right, and the Bolshevik coup only succeeded at the cost of - again - sparking a civil war. The Mensheviks and SRs were both onboard with the provisional government; neither of them were likely to attempt a coup. Most of the right-wing elements had been stripped of power, and the military refused to follow a right-wing putsch attempt. If Lenin had stayed home, so to speak... what faction does that leave to attempt a coup?

It hardly seems ridiculous to think that the legislature that everything since the overthrow of the Tsar had been working towards - complete with arguments and concessions with competing factions - finally assembling after the long-awaited elections might have forged something lasting had the Bolsheviks not closed it down by military force, yes.