don't worry anon, we're all annoyed by it as well.
sadly, there are some in-universe explanations for everything
- the new republic didn't take the first order as a serious threat, since starkiller base was a secret, so leia had a hard time getting supplies to the resistance, hence only x-wings
- (this isn't confirmed, just my speculation) the first order put their resources into two things: manpower and starkiller base. this lead to them only having tie fighters.
- the whole purpose of the movie was to ignite nostalgia for the old films (lol fuck the prequels, rite guis?) and make money. guaranteed, we will see the return of a-wings, y-wings and b-wings as well, god forbid we get anything original.