Because Gaim was easily comparable to early Heisei series in terms of overall maturity, if not more so(despite obvious Ryuki parallels, blah blah blah).
Drive I am not familiar with but supposedly @anon68675807 and @Takua say Drive has turned out pretty darn good, and we have High Hopes for Ghost.
Heisei also gave us the extremely light hearted Den-O and Kiva, as well as the frankly lackluster Decade and Hibiki’s second half.
All three eras have their strong and weak seasons.
And while Neo Heisei in general could be considered lighter and softer, IMO, it doesn’t detract any of the quality, especially in the case of W, OOO, and Gaim, and moderately in the case of Fourze, though I will admit that one is vastly flawed, and Wizard wasn’t that great.