I support him now based on peak alone, however I think it'll be hard to deny him if he makes it to 2,000 innings. His career so far is roughly equivalent to Sandy Koufax's six-year run from 1961 to 1966:
DeGrom: 1635 IP
Koufax: 1632 IP
DeGrom: 1248 H
Koufax: 1171 H
DeGrom: 2.63 ERA
Koufax: 2.19 ERA
DeGrom: 1966 K
Koufax: 1713 K
DeGrom: 148 ERA+
Koufax: 156 ERA+
DeGrom: 0.986 WHIP
Koufax: 0.970 WHIP
Etc. etc.
So deGrom for his career has done about what mostly got Koufax in, which was that stretch. Now if deGrom can get a few more years in where he just pads his counting numbers -- he's already almost to 2,000 Ks and should be there by the end of the year -- then he'll look that much better. For peak cases, even historically, wins weren't the be-all-end-all. Dizzy Dean, Lefty Gomez, Rube Waddell, Ed Walsh etc. all got in with less than 200 wins, back when 200 wins was more common.
DeGrom probably has two more years with Texas after this. Assume 150 innings each season and that should get him to 2,000 IP for his career, and assume a good amount of Ks and that should get him near or past Koufax's career total of about 2,400.