Recency bias. Last year StL won, so the mantra becomes get bigger. A few years ago Chicago won so it was get quicker. Next year, everybody will be trying to get older.
Don't let a hot streak with a hot goalie fool you into thinking spending a lot of money on old guys is the path to victory.
But to put it into the context of this discussion, long term commitments to older players can be a death sentence for competitiveness. OTOH an occasional very good older player on a short term contract might be a good idea. The thing is that you pick these guys up in FA for 1 year at a time, maybe 2. No long term commitments.