If we're talking full content (including non-sex scenes), I do think it's quite a bit longer than most prologues in games. You get:
1. Introduction to MC (including masturbation and Nina porn)
2. Introduction to Sasha and Mia while driving to the club
3. Introduction to Kendra (in the club, with some stripper shots)
4. Jail scene (MC x Kendra or Mia x Kendra NTR)
5. Scene back home with Sasha and mom
6. Spying on mom
7. Going to the house and meeting Natasha and Nina
8. Aftermath and all the flirty scenes with Nina
So on a pure sexy times level, no, there's not a whole lot of content, but if you look at the game on the whole, the prologue is filled with much more content than most other prologues, in my opinion.
That's not me saying it's an excuse for them to have six-month gap between releases though.