Let's see. Trade in players that are questionable for 2 years and maybe win a premiership.
Big risk. Very improbable it would work given that they wouldn't get much game time on our list. The players Sydney has recruited under this type of scenario were given game time due to the fact Sydney were in transition.
Then compare it with the future in 2 years. Possible retirements: Glass, Embley, Cox, Kerr. Add to that those "depth" players you traded in and we are left with a List that lacks a few younger players coming through that we could have blooded in the next 2 years.
Add to that I think our list is good enough to win a premiership without them. Why bother and risk the short term future.