First of all, get over the numbers. Yes they make obscene amounts of money, but that's the way it is. And the difference of 60k vs 70k, or 7 million vs 8 mil, or $6/hr vs $7/hr is just as legitimate to them in their occupation. Are cops, teachers etc. more deserving of big paydays? Of course, but this is the system we have.
Now the reality is that both sides are really trying to rip off the other. You hope for undervalued rookies (like Zach and JT were) to outperform their salaries (underpaying them). Once they prove their abilities, they want a big contract that pays even if they don't continue to perform at the same level, with as much guaranteed $$ as possible (getting overpaid). First round draft picks get paid ridiculous amounts based on speculation (often way overpaid).
The only equitable system would be based on a base draw salary by position and maybe years in the league, then a set bonus system based on productivity. So a rookie DT might get a lower draw, but if he gets x amount of tackles, sacks, etc, it goes up. TO might get a higher base salary due to his years in the league and wr might be a higher paying position. If he performs like he has, he would earn huge bonuses, if he underperformed, he doesn't break the bank.
Of course, this would never happen. Players union wouldn't go for it, and it would be too difficult to figure cap, etc. But barring that, good players are certainly within their rights to try to extract as much $$ as they can, just like the team can decide to let him sit, or cut him when he's not performing to their expectations. Is he selfish? Of course, but the days of teams paying veterans out of loyalty are over, otherwise we wouldn't have Seau, so it works both ways.