In terms of combat mechanics I’d say DBFZ is building off the direction established by MVC2 and MVC3, and Infinite took a decidedly more modern tack that sorted it into a different class entirely, alongside BBTag, both of which would eventually go on to inspire Power Rangers: Battle for the Grid.
MvC players often find the one they like and stick with it. Few games get anywhere close to contesting MvC2’s room for skill expression, so if you’ve devoted your life to playing Magneto or Sentinel in that game then little else will satisfy. UMvC3 doesn’t quite get at those peaks but does get within striking range, and has a much more playable roster, so if you’re a fan of Marvel and Capcom IPs together (instead of like, the X-Men), UMvC3 is probably the richest place you’ll get to see these characters play together. MvCI has a lot of really cool things going for it – the infinity stone system had a ton of potential, and the tag system redesign is absolutely fantastic in how it manages to crank up the action while also streamlining the way teams work, but the character selection and awful art doomed it to an ignoble end.
Anyone who was still playing MVC2 when MVC3 came out likely did not stick to MVC3 for long, because it wasn’t what they wanted (which was: more of the same, please, but Better and Newer). I think this is also true for MVC3 to DBFZ as well. Anecdotally, the local UMVC3 scene has minimal overlap with DBFZ, in part because the IPs are different (and IP celebration is a critical part of the appeal of these games), but also because DBFZ’s possibility space feels dramatically smaller and flatter than either MVC2 or MVC3. So while DBFZ has certainly won the title for Best Tag Team Fighting Game, it most likely did so with the support of a different audience.
Personally, I got about 80 hours into DBFZ after years of UMVC3, then I looked at the game and thought to myself “I don’t want to do this all again in a game I like less than the game I just did this with.” These days I dust off my UMVC3 team once a month at locals and have a blast.