#1 should not matter. Market rate is the rate I should expect. Just because I have 20 years of experience does not mean I'm going to get my rate for a Jr PHP job. The complaint is more likely that most companies do not need many people with that level of experience. The old phrase too many generals and not enough soldiers comes to mind.

#2 is changing because we are entering the baby-boomer phase of IT. It was recent that that there were not many people programming, and then the field blew up with tons of young people coming out of college. Those young people are now turning into older people. Where I work now we have a median age for the IT staff in the high 30s. I don't think anyone is under 30 anymore.

#3 can be true of anyone, depending on how well they have managed their career. Sadly, I have interviewed people with '5 years experience' who learned their job in 3-6 mos. and have just continued to do the same job for 5 years. Their actual experience ends up not being much more than a recent college graduate.