Probably because getting value for these deals is very difficult to do. I think a lot of people underestimate how good these guys are and how good their contracts are. If the goal is to win, and I hope we can all agree that it is, these are two vital pieces. The problem with this team isn't that they're hanging on to Bautista and Edwin, it's that they've supplemented them with less than ideal pieces, especially value wise.
I know a lot of people dream of the kind of talent that elite players can bring back in deals, but if you don't have the management team in place to correctly identify talent (which we don't; an altogether different problem) than what's the point of trading known elite talent for prospects? To be honest, I'd rather the Jays hang on to these guys and try to win, than offer them up for another organization's "track stars", whatever that means.