They're also usually being ridiculously hyperbolic. At most, non-magical D&D characters are in the category of pulp adventure characters of the higher end. You can make weird arguments about mages, but even there, as noted, D&D characters have a limited tank, something extremely rare with superheroes.
And nothing suggests level 3 looks anything like a superhero.
It doesn't matter whether you do or not; the fact the things some supers use are equipment-like exists only in the sense of an occasional plot device. You almost never see a superhero out scrounging for more gear (and if you do they're very much at the bottom end of the scale and/or its a one-off plot event).
There's a fine line here. When you're looking for a fix for problems, using optional rules and house rules is one of the first places you should go. When you're talking about the general suitability of a system for use outside its normal purpose, though, if you go there you're in the "any system is good for anything camp" and no, I'm not following you there.