I think most people just see the PG as an interregnum. The only real scope for WIs is whether it gets overthrown in favour of a left-wing tyranny (Bolshevik or similar) or a right wing one following a White victory. Given Russian history, it's difficult to envisage any other options.
Or... what if Lenin's train never arrived in Finland, where he disembarked for russia, and was instead captured by provisional-supporting security on his way there from Switzerland?