Although I am not a 121 pilot I do have a couple of observations to point out that are positive.
-Air travel will increase across the world including the US for years to come. There are just a few life changing events that could slow it down. The population is growing every second that goes by.
-I see lots of talk of consolidation. Airlines may try to shrink but others will just grow in their place(reference above). I know this industry has been hard for a lot of people the 15 years but growth will happen and pay increases will happen to if pilots would learn to stick together and not cut each others throat all the time (novel concept, huh??)
Will we see a pilot shortage? No one knows until it happens! I can see plausable facts from both sides but we do not know the future. I feel we will see movement and demand go up quite a bit from what most of us sub 40 guys have seen in past but no one knows how high. The best thing we as pilots can do is to try to make the future of this industry the best we can. Things in every industry suck some no matter how awesome you might think they are.