Trade Deadline 1998:
Randy Johnson (struggling in '98 w/ a 4.33 ERA, 1.30 WHIP, and only 2 months before free agency) traded for Freddy Garcia (34.2 career WAR), Carlos Guillen (27.7 career WAR), John Halama (5.6 career WAR).
Trade Deadline 2008:
C.C Sabathia (2 months & then a FA) traded for Michael Brantley (34.3 career WAR), Matt LaPorta (-1 WAR), Zach Jackson (-1 WAR), Rob Bryson (0 WAR).
Trade Deadline 2016:
Aroldis Chapman (traded to the Cubs by the Yanks for 2 months & then a FA... and Yankees signed him as FA!) traded for Gleyber Torres (14.4 career WAR), Billy McKinney (0 WAR), Adam Warren (6.6 career WAR), Rashad Crawford (0 WAR).
Trade Deadline 2002:
Bartolo Colon (2 months & then a FA) traded for Grady Sizemore (27.8 career WAR), Cliff Lee (43.2 career WAR), Brandon Phillips (28.4 career WAR).
TWO YEARS + 2 months of Skubal is worth SIGNIFICANTLY more than any of the two month rentals above.
You don't know what you're talking about.