Sure it is. But it only works until one of the LCC's puts service on that route. At that point the RASM at CAL drops when they price match and they lose money. The RASM on routes with LCC competition is probably very low. The problem CAL has is there aren't many domestic routes these days without LCC competition. So they get their money from international flights which works great until they open up the skies and LCC's head across the pond.
The costs of LCC's can do nothing but increase as the companies age. It also appears that the LCC's are running out of places to fly as the competition heats up. I agree, the RASM is probably very low on competing routes, but as long as it is positive they will continue to fly it.
I would think it would be prohibitively expensive for a LCC to start an international operation from scratch, but that is just my opinion.