It may be set as a '1950' tech simply as a malus to make it harder to complete research.
I've never heard it from the Devs officially, but at this point I'm assuming that the conventional game ends at 1948.
You are right. This is a possibility. It might be that the game just runs until 1948, but with a lot, a seriously lot of effort you might be able to make better aircrafts earlier than historically they were created, before the game ends.
I mean, for example, if Germany has won, who is to stop it from testing the Maus and then creating a real functional super heavy tank by 1947? Or IJN to create a really powerful version of A6M Zero or a new plane entirely?
- 1