I don't want to get too deep into semantics here, but I'm saying what I think bkox is saying, too.
I'm much more comfortable saying Cave, for example, has missed his chances than "blown" them. Like 'z' above, I'm perfectly capable of rooting for Cave or Clemens, but hoping the Phils have a better option for their ABs. I'd love to see both those guys make a career somewhere and earn a pension, although with Clemens the pension is probably not particularly relevant.
BTW, here is another Chris Coste exception from the really old days:
"Dazzy Vance exceeded (current) rookie limits in his first full season of 1922 following cups of coffee in 1915 and 1918. He had turned 31 during spring training of that year. He remained an above-average pitcher through age 40, including leading the league in strikeouts each of his first seven seasons, wins twice, ERA thrice, shutouts four times, strikeout-walk ratio eight times, and won MVP in 1924."