This is almost complete conjecture based on one data point on my part, but with the Civic silhouette coming today I'm starting to wonder if PD are thinking of moving towards more Forza Horizon/The Crew style "playlist"-based career events for GT8, rather than the current more static model where for most event types you can use the same car for the whole thing.
It'd make sense as to why they have been so focused on making sure the Civic/GT-R/Evo/911/TT etc lines are complete. If instead of, say, just having some Evolution Meeting races that take all the Evos, the intent is to have you go through the history, doing a race in the I-III, then a race in the IV-VI, then a race in the VII-IX, then a race in the X/Final. Maybe if it's joined up enough, winning that then rewards you with say an Evo rally car that you can use in the '90s part of a rally playlist, though that part might be wishful thinking on my part.
I could be super way off with this, but it makes sense in my head, and it'd be an improvement in terms of tying the game into car history (a big part of the series nowadays) than just having some text everyone skips through.