The A319 doing the transatlantic routes is a specific longhaul version, which is used IRL for such flights (such as this).
That is only St. Johns - London. Far from Paris - New York, or London - New York. And with a two class cabin.
BA was also doing it with A318s from London City, I think.
True, but they only carry 50 seats, and even then they need to refuel in Shannon when heading west.
Either way, even if it wasn't done, that doesn't mean airlines shouldn't be able to do it if the aircraft can make the distance. I would also point out that the longer range A319 costs considerably more (59 million rather than 47 million).
Comparing the shorter range A319 and the 737-700, the stats are fairly similar, the 737 has a bit of an edge on seats, speed is about the same, and the A319 has the edge on range. I think this is more to do with problems in the cost formula - as seats seem to be overrepresented in terms of price setting. Compare the A319 with 2000 range versus 4000 range - the latter is only 12 million extra - a 300 nm difference between the A319 and 737 wouldn't be so great I should think. The difference may also have something to do with the fact the 737 series is older (the construction date of the aircraft type certainly affects price, I'm not sure if the system "knows" that the 737 is an older aircraft, i.e. with roots as old as the 737-100).
This doesn't make sense to me. The 737NG is the newer of the two families. The A320 family is from 1988?, the 737NG is from 1997. The A319 is from 1996. The 737NG is in no way related to the 737-100, -200, -300, -400 or -500, other than in name.
And if prices are made up, then why is a more capable plane (The A319, long range version) cheaper than the least capable 737-700? The less capable A319 should cost almost the same as the 737-700, while the more capable A319 should be slightly more expensive than the 737-700HGW.