The fact that offensive lines have evolved is the reason Ends are more valuable in today's game, more so than ever. Putting pressure on the QB is the focal point of the defense, and most pass pressure will come from the ends.
The fact that the NFL generally pays Defensive Ends better is evidence that I'm on to something. At least, it proves that the NFL values Defensive Ends over Defensive Tackles (though both are very important).
Also, why are offensive tackles considered to be more valuable than offensive guards? Same reason.
Then why are NFL Defensive Ends paid more than Defensive Tackles?
Wholly disagree with this, especially when you take into account supply/demand.
What's the support for your statement that DEs are more important than DTs? Is it that they're paid more in the NFL or is it that football has become a passing game?
5 of the last 7 NFL drafts have a DT (3-4 SSDE, the Richard Seymour position, counts as a DT to me) taken before a DE. I strongly believe that, whatever the glamour position may be, a defense starts inside. The reason is shockingly simple: the most efficient play for an offense (who's charged with the task of marching toward its goal, the end zone, in the most efficient way possible) is to run directly down the middle in a straight line for as many yards as possible. The defense's natural reaction is to be able to control the middle of every play.
In fact, I think you've seen general managers believe in this so much that it forced an emphasis on DTs --> which led to offenses adjusting to a spread sets --> which led to the need you've described for edge guys. However, what will you see if teams decide to de-emphasize DTs? Offenses will once again adjust for efficiency. They'll run I-Formation HB Slams for 6-8 yards at a time until defenses once again adjust.
And, therein lies the beauty of football. It's like the Free Market. Supply, demand, corrections, adjustments in the name of efficiency. And, in the end, the name of the game is whatever produces the most output (for an offense) or whatever slows down that output (defense).
Football is life?