NATIONAL HARBOR, Md. -- The Winter Meetings are over. The Hot Stove still smolders.
Chris Sale, Aroldis Chapman, Adam Eaton, Ian Desmond and Mark Melancon have new teams ... but Edwin Encarnacion, Andrew McCutchen, Ryan Braun and Chris Archer do not.
Here's what we learned over four days at the Gaylord National Resort & Convention Center:
1. The Bullpen Revolution is real
On Monday, Melancon set the Major League record for a relief pitching contract with his four-year, $62 million deal  to close for the Giants.

Less than 72 hours later, Chapman took ownership of the distinction by returning to the Yankees on a five-year, $86 million contract.
Clearly, MLB team executives took note of the past several postseasons, as the Royals, Indians and Cubs won pennants or World Series championships largely on the strength of deep bullpens. Turns out, closing "committees" -- a favorite concept of the analytical community -- work best when there's a dominant arm in the ninth inning.
Chapman, Melancon and Kenley Jansen became free agents during an optimal offseason, with demand for their skill sets reaching an all-time high among those whose opinions matter most: MLB owners and general managers.
2. Rivalry, renewed
Seven straight seasons have passed without the Red Sox and Yankees finishing 1-2 in the American League East, in some order. Perhaps that's about to change.
The Yankees can portray the Chapman signing as a long-term play that allows them to compete for championships in the future. And that is true. But this also is a throwback to the Yankees of old, an emphatic sign to the industry that -- for all the excitement around Gary Sánchez and Gleyber Torres -- the Pinstripes remain capable of humbling the rest of the industry through the sheer might of their financial resources.

Red Sox president of baseball operations Dave Dombrowski seemed to acknowledge as much -- good-naturedly -- when he saw Yankees general manager Brian Cashman at Thursday morning's Rule 5 Draft, less than 12 hours after the agreement with Chapman. According to Joel Sherman of the New York Post, Dombrowski threw his arm around Cashman and said, "The monster is back."
Of course, Dombrowski did his part to reinvigorate the rivalry this week, with trades for Sale and Tyler Thornburg and the signing of Mitch Moreland.
3. White Sox, finally, are open for business
The White Sox's bold approach to the Winter Meetings received immediate plaudits from the industry -- and the team's fans -- revealing an undeniable truth about today's game: Rebuilding is no longer a shameful exercise.
The trades of Sale and Eaton were welcomed by many White Sox supporters, because they've seen the same blueprint work elsewhere -- including, most recently, about 10 miles to the north. Thanks to Jim Callis and Jonathan Mayo of MLBPipeline.com, among others, fans know more about prospects than ever before. Yoán Moncada, Lucas Giolito, Michael Kopech and Reynaldo López represent hope to White Sox fans who haven't cheered for a playoff team since 2008.

And so the White Sox have every reason to continue their newfound course, with trades for José Quintana, David Robertson, Todd Frazier and perhaps even José Abreu. As one National League executive observed this week, the baseball world's (justifiable) fixation on the Cubs makes it easier for the White Sox to initiate a long-overdue rebuilding plan, away from the spotlight.
4. Age and versatility really matter
Last offseason, a clear trend emerged on the free-agent market: Teams shied away from significant long-term commitments to position players unless they were young, brought unique defensive value, or both -- as in the case of Jason Heyward.
At the Winter Meetings this week, we saw more of the same: Carlos Beltrán, Matt Holliday, Carlos Gómez and Moreland all signed one-year deals. Desmond, 31, had appeal to the Rockies because of his defensive versatility, overall athleticism and strong leadership qualities. But among all of this offseason's free-agent position players 33 and older, the longest contract has been Kendrys Morales' three-year, $33 million deal with the Blue Jays.
Encarnacion, 34, and José Bautista, 36, remain unsigned despite ranking second and seventh, respectively, among Major League hitters in home runs over the past five seasons. Mark Trumbo, who ranks 10th on the same list, also remains available; he is 31 but rates as a below-average defender in right field.

5. Dodgers, Pirates could help each other
The Dodgers departed the Winter Meetings without making a major transaction, despite obvious needs at second base, third base, the outfield and the back end of the bullpen.
The Pirates are in an awkward situation with their longtime franchise player, as McCutchen was discussed in trade talks with the Nationals and Rangers before those teams satisfied outfield needs through other moves.

With the Pirates running out of possible destinations for McCutchen, the Dodgers could be the best remaining match, especially given their need for right-handed hitting.
The Dodgers have the most committed payroll for 2017 among all MLB teams: $188.2 million, according to Spotrac.com. As a result, their best course could be to trade with the Rays or White Sox, who have the players to formulate a blockbuster package addressing multiple areas of need for Los Angeles.