They absolutely do not have 3 of the best 4. Chapman and Kimbrel are a wash, but Barnes is better than any of their guys this season. You're overstating that advantage, again.
I’ll give you that Barnes’s numbers
this year are as good or better than any of the non-Chapman Yankee guys, but I think we’re supposed to consider track record too. Jed Lowrie has a higher WAR than Manny Machado this year, but I don’t think anyone would argue that he’s the better player or more likely to play better going forward (yes, hyperbolic example thrown out for effect, before anyone jumps all over the analogy).
Past 3 years - Barnes vs. the Yankee guys (sorry, on mobile so can’t make pretty charts. Left off Britton because coming back from injury he’s pretty much a wild card and I’m not sure past numbers really mean much).
xFIP
Barnes - 2.60, 3.27, 4.05
Betances - 2.03, 3.76, 1.75
Robertson - 2.92, 2.76, 3.99
Green - 3.41, 2.55, 3.67
WPA
Barnes - 1.31, 0.88, 0.61
Betances - 1.21, 0.73, 0.47
Robertson - 0.81, 2.88, 1.48
Green - 1.00, 2.02, -0.31
ERA+
Barnes - 189, 119, 111
Betances - 179, 158, 140
Robertson - 121, 240, 117
Green - 159, 248, 91
K/9
Barnes - 13.9, 10.7, 9.6
Betances - 15.6, 15.1, 15.5
Robertson - 11.8, 12.9, 10.8
Green - 10.8, 13.4, 10.3
I will absolutely give you that through a little over 100 games this year, Barnes has been as good or better than those three guys, but this is the first time in his career that’s been the case. Yes, he’s young and improvement makes sense, but relievers are volatile and the other guys have done it for longer. In the past 3 years, all three have at least once put up numbers better than what we’re seeing from him this year with floors at/above his.
Let’s put it this way - gun to your head, who do you choose to pitch the 8th inning of tied game 7 in the ALCS? I’d pick Betances without hesitation, and I struggle to imagine many neutral observers doing differently.