Okay, then please give exceptions to this generality.
Computer programmers. The population has grown dramatically, and yet more pay is achievable now than previously. Doctors are another good example. At any rate, pay isn't the sole metric (as you seem to think) even if you adjust pay for inflation. Look around you and compare the life of the average person to the life of the average person 60 years ago. It's not even worth it to look further back than that.
You take exception with the statement that when I look to hire someone "I seek to maximize my reward: that is, to get the most skill for the least amount (of pay)." It's always been that way, with every job, and it's nothing new:
Assume I want to have my lawn mowed. I'm willing to spend up to $1.00 per week for this job. You come along and you're willing to do it for $0.50. I'd be stupid to pay you $1.00. If someone else came along and offered to do the same work for $0.40, I'd be stupid to keep paying you $0.50 (assuming he does just as good a job, of course). And so on. If you wanted to charge $1.50 to mow my lawn (because that's what you need to charge to make ends meet) I simply wouldn't hire you. There's nothing wrong with that. I don't owe you a living; nobody does.
This isn't rocket science.
It's simply cost-benefit analysis.