It's weird that on paper this team is no way near to that of the 17-18 team but the on ice results (by both traditional and fancy metrics) are right up there with that team.
The core of the 2017-18 team was much younger.
There had a handful of high-quality older vets (Perrault age 30, Little 30, Wheeler 31, Byfuglien 32, Enstrom 33, Stastny 32 after they traded for him), and a few players (but no stars) in their late 20s prime (Tanev 26, Chiarot 26, Myers 27, Kulikov 27).
This older, top-heavy roster was supplemented with a huge number of U25 (under 25 years of age as of Feb 1st, 2018) players who had big roles:
19: Laine
21: Ehlers, Connor, Roslovic
22: Morrissey
23: Trouba, Copp
24: Scheifele, Lowry, Hellebuyck, Armia
...this ignores bit players like Roslovic and Petan
Those players are now 6 years older. The older cohort has moved on, and the younger group is in their prime.
The current roster has almost no U25 players at all:
22: Perfetti
23: Gustaffson, Kupari (both currently on IR)
24: Vilardi
...that's it -- those are the only players on the current team who are younger than Mark Scheifele was in January 2018.
Hard to believe, but Vilardi is the 2nd youngest player on the team during this current winning streak.
Ages for the rest of the regulars in the current roster:
25: Barron, Samberg, Jonsson-Fjallby
27: Ehlers (6th youngest player on the team right now)
28: Appleton, Pionk, Morrissey, Connor
30: Iafallo, DeMelo, Hellebuyck, Lowry, Brossoit, Scheifele
31: Namestnikov, Niederreiter
32: Schmidt
33: Dillon
I don't want to make the argument in detail, but I think it's hard for even high-quality young players to win consistently in the NHL. We saw a little of that last night with Columbus, where half their roster is currently U25 including Fantilli (19), Jiricek (20), Sillinger (20), Kent Johnson (21) and Chinakhov (22).
So I think a hindsight memory of 2017-18 will tend to overrate how good the younger players were at the time, including Ehlers, Connor and especially Morrissey. That team relied a lot on the younger players, but they weren't quite as good yet as they've since become.
The current version of the Jets is much more in its prime.