It seems like we're forcing a lot more TOs this year than years past, so maybe the on-ball pressure is a huge chunk of why our D has been largely successful.
As for forcing wing players toward the baseline, that's a pretty universal concept. As you said, it adds the baseline as another defender, and with sound helpside D, it cuts off an entire half of the court, and a player is either forced to take a low-percentage shot with no backboard or pick up his dribble and likely get trapped. His only other option is to back it back out the way he came, in which case the D did its job.
Once a player gets to the middle, if he has anything but terrible court vision, has pretty much beaten the D already, because if he's not open, someone else is, and he has the whole court to work with.