It's not that any was necessarily "the guy" to get an elite young starter but rather the cumulative effect. For example, it's entirely possible you might have been able to work a deal around Soler/Jiminez for Q rather than Cease and then you have Cease for the next deal and so on.
I think arguing Dylan Cease and Jorge Soler have had similar trade value in the past twelve months to be highly suspect. Soler two or three years ago sure was at that level but after a massive regression in ability to hit MLB pitching with a continuing of nagging injuries has led to Soler being a drastically lower value prospect. Basically, when the Cubs traded Soler and Candalrio, I didn't care that those guys were leaving because they had never shown an ability to be a high level player on a ML team and if they playing for the Cubs then the Cubs likely weren't contending for a WS championship.
And the thing is Briton isn't even cheap. He's likely $3-4 mil less than Davis is going to get next year. Ok so you are giving Davis 3 years but then who replaces Briton? For example, the last 2 years Davis made $10 mil for the cubs and Chapman made $11.325 mil. Granted in Chapman's case he was a half season rental but my point here is you're saving $3-4 mil a year to not sign a guy and you're giving up a slew of decent prospects. If they go the Briton route they've effectively signed a closer for 3 years $33.325 mil or roughly $11 AAV.
Again, the problem with paying Wade Davis is that closers, especially at his age, are notoriously terrible.
Since 2000, only four relievers have been 6+ fWAR for ages 32-35
Rivera
M. Thornton
Wagner
Betancourt
Five others have been 5-6 WAR
Hoffman
F. Cordero
Quantrill
Otsuka
J. Nathan
That's it. For almost the past 20 years, only nine pitchers have returned what you'd call the most optimistic value for Davis seeing as he just was a 1.1 fWAR pitcher last year. That type of risk and price is simply why I don't see how Davis has any value to any contract he'd sign for.
I have a problem paying for saves in terms of long term money. Trading Soler was not paying anything to get Davis. Trading something not off the MLB roster and the top prospects is an adequate cost to get Britton if you trust his arm.
If you don't like Davis as the guy to sign long term fine. But this continual trading of prospect rather than signing someone is just stupid. Find a guy you like and pay him the money. There's also the issue that because the cubs bullpen has been in such flux season to season you end up where they are consistently dealing in season for guys like Montgomery and Wilson.
It's both though. I want to sign two guys (McGee and Morrow) but if you told me that you could get say Britton and sign Morrow for a 2 year deal, I'd do that instead. Morrow is a good backup if you truly believe you need a "closer" and then you have the hope that Edwards or someone else pops as a late inning guy.
I mean, a prospect has as much value to me in a trade for a player than he does to the future MLB team he would be on. Not every player and prospect is going to be valuable to you because of his on field play; that's unrealistic.