Actually, he's been a half season pitcher in 3 of the prior 6 seasons, and he may last all this season (probably not as a starter though, but there is a chance he lasts all year 4 of the last 7, so it may not be over half the time.
I agree, that when he does pitch a full season, he has only been very good once, so-so once and very bad once. I'm not sure I'd call that "sucks", but if you want to say it, I won't argue too much. Three of his 4 half seasons have ranged from pretty good to near legendary great.
Again, I will say, he's been more durable than some seem to think he has been, and he's had more good stretches than some seem to want to give him credit for. He has certainly sucked recently, and with pitchers, it's often said they are only as good as their last start, so I get the sentiment over his last 14 starts. The guy is rotten right now. Nobody is saying he isn't.
Just don't let the now cloud historical truths. There's no doubt, Buch has sucked over the last few years too often for anyone's tastes. I caught a ton of grief from a poster a couple years back for listing Buch as our #5 starter after his 2013 season of greatness for 16 starts, so I get the point people are making.
My only point being made here is that over his career, he has been more durable than some think and a decent to great pitcher for more stretches than some want to give him credit for.
Baseball is a "what have you done for me lately" sport, and I get that, but history is history and Buch has had some fantastic stretches, some very good stretches and some decent stretches mixed in with too many DL stints and bad stretches for anyone to overlook.
3 near full seasons
2010 Very good
2012 Servicable
2014 Very bad
4 half seasons
2011 Pretty good
2013 Excellent
2015 Very good
2016 Horrible (still in progress)