It has nothing at all to do with depth.
THEY NEED A NEW COACH.
See: Penguins, Pittsburgh, 2016 for an example of how necessary this is sometimes.
Uh, Penguins completely reworked the roster for their Cup run.
That SC team was put together over little more than a year. 14 of 22 players were changed.
The only "holdovers" Crosby, Malkin, Letang, Hornqvist, Kunitz, Maata, MAF
So what the Pens show is the need to make some trades!
Lovejoy and Cole added in trades in 3/15, Kessel and Bonino were added that summer in trades, Cullen and Fehr signed as FAs, Dumoulin promoted at age 24.
Promoted Sullivan and:
12/14/15 traded Scuderi for Dailey
1/16/16 traded Perron and Clendening for Hagelin
2/27/16 traded 3rd rd pick for Schultz
called up Kuhnhackl, Rust, Sheary, Murray from the AHL