So, DMC got a important element of the saga dead at the very first game; for getting Vergil again in game they needed to make a prequel; now they invented Nero to replace Dante because Dante is now too old and they forced Nero down our throats making him Vergil's child, in a way they are unwilling to explain, but Nero lacks twin's charisma.
Definitively DMC story is garbage at this moment, it's a total mess!
Ok, mates, so this meaning to have Vergil we have two options: or they go with a DmC sequel ( where Vergil didn't die or he was resurrected or they make a total rewrite of the story.
No more prequels, since it keeps the story from progressing.
They wrote out Vergil in DMC1 (Granted, somewhat ambiguously) because it was a new IP and there could never be any guarantee of a sequel.
It's the same thing with Bayonetta 1, they basically wrapped up all the main plot threads and had her kill
god at the end of the game. And just like how Devil May Cry could do with Vergil, the next installment was made by adding in a ton of new elements to the universe that weren't referenced before, and just straight-up inventing
another god to kill out of the blue.
Back to DMC, let's just assume that Vergil really did die after the third Nelo Angelo fight, or even before when he faced Mundus.
What does that actually
mean? There is almost no context for what results from death in the DMC universe, other than powerful Demons turning into weapons - Which Vergil did not. Even then, we don't know what could come of that in time.
The cosmology is like a blank slate. There are no rules for Humans and barely any for Demons, much less someone like Vergil. There are a million and one easy ways they could write him back to life.