I guess I'm missing something in the math here. You can't get a Part 121 job now without 1500 hours. You can get a CFI at 250. So there are well over 1000 hours you have to get somehow, and there are only so many jobs banner towing and the like. So practically speaking, nearly every aspiring airline captain has to spend at least 4 times as long instructing as the amount of instruction required to get a CPL and CFI. The airlines can't poach them during this time, because they don't (can't) have an ATP.
I think the article is just a whinge by a Part 141 outfit that is paying peanuts and can't keep staff. That said, it's clear that since the requirement for 1500 hours in the right seat, the whole training system is pretty broken and at some point the airlines are going to have to figure out how to fix by (shock horror) spending money.