It's not a matter of "another bad year," it's a matter of you don't sell low.
Hernandez, Rupp and Galvis won't garner enough to make it worth dealing them, you don't trade decent starters for good but not blue chip prospects when you have plenty of "good but not blue chip" prospects already in your system - and if you could trade them for blue chip prospects, given their ages, they should be retained as part of the core of a contending team in a couple years (if they're that good, why get rid of them?). These are the guys you trade for prospects AFTER Crawford and Alfaro have made it to the major league team and demonstrated they're ready to become every day starters. In that case you're trading surplus ML talent that would be too expensive to keep to build prospect depth. Keeping them another year isn't risky because their trade value isn't that high (unless of course, some fool overvalues them).
Guys like Hoskins and Cozens have limited value right now, they're not considered top prospects, if they have big seasons at Lehigh, their value will skyrocket, if not, you haven't lost much. Same with most of their young pitching, in a year, they'll either have the same limited value they have now or a lot more value if they have good seasons.
The point is there are few deals they can make right now that will improve this team down the road, the objective isn't to get to .500 and hope to have one season when the stars align (that's what small market teams do), but to build a solid contender for the long haul to get back to the WS. So adding players who are close to or over 30 years old doesn't further that objective. The only reason to add an older player this season would be as a patch while the prospects mature at Lehigh - i.e. a corner OF who can hit. And the only resources you should use on that player are money and 3rd tier prospects.
This is why the international market is the best opportunity to spend money, a player in his prime at a position of need would be worth an overpay.
