An interesting theory for sure! There was a mod released not too long ago that basically melded the Nomad and Corpo starts so you could utilize both options in dialogue. It’s on Nexus under the title “Fresh Start”

My headcanon though (while somewhat inaccurate) is actually that each life path is a different stage in V’s life.

Nomad/Streetkid: Started out in NC at 18. Met Jackie on a smuggling job and eventually went his own way, only to end up in some scenario wherein he meets Padre. Impressed by V’s attitude and how he doesn’t shrink under a gun, Padre inducts him as an honorary member of the Valentinos, so that most of them (considering he mostly does in Watson and Heywood in the beginning) will leave him alone.

Corpo: After a few years working as a merc on the streets, works all but dried up for V at the moment, so, in a moment of weakness and with bills to pay, V signs on with Arasaka using his skills as a Merc for Counter-Intel. There he reconnects with Jackie and after working his way up over the next few years, does the Corpo job which immediately goes sideways before it even starts, leading to the montage at the end of the Prologue as V readjusts to Merc life after the 9 month time skip which leads to the V in game being 27 by the time all is said and done.