Exactly. Rebuilding teams now understand that good young players who are controllable carry the most value and if you suck - there's no need to hang onto those guys through the lean years. If you're going to part ways with a top prospect - get someone with years of control. Rentals are typically an awful use of assets.
Realistically, the Jays should probably look to deal Stro, Sanchez. Those are the guys who are going to net you Frasier. The return for rentals is not going to stock our farm system with top prospects like it would have 5-10 years ago.