What a blessing this is to the average fan. The lack of a guaranteed paycheck does wonders for an athlete's motivation and commitment. You have less ridiculous demands for trades, or complaints to the GM that a guy isn't getting the ball enough. Because if you blink, or get out of line on the depth chart, you might just end up throwing luggage by April. Football doesn't care.
Football moves on.
Take the example of Ryan Leaf. He couldn't beat out Joe Hamilton for the 3rd QB spot on the team. And everybody has moved on. Thank god only his bloated signing bonus is still on the books with San Diego. Otherwise, if he were an NBA player picked that high, he'd have guaranteed money, and some team would be forced to live with him until the deal expired.