I hear EPII at about 95% of Masses in the area. Once in a blue moon I’ll hear EPI (only ever celebrated by one priest, who will rarely recite it if it is the occasion of one of the Saint’s names mentioned in it) and somewhat more often EPIII or EPIV. The preference is for EPII, as has been said, because of its brevity.
In a nutshell, it has to do with some of the fashions that prevailed in the 1960’s and 1970’s, when the bulk of the work on the topic was being done. Primary among them was a fetishization of early Church disciplines. It was commonly believed that the Roman Church had strayed too far from the early Church’s practices and that it was necessary to hack away the growth in order to get at a more authentic core (a highly reductionist view, IMO). The scholarship at the time supported the idea that EPII predated the Roman Canon, that in fact the Roman Canon grew out of it; and no one today takes that scholarship seriously. Its authorship (supposedly by Hippolytus) is now disputed; the earliness of its origins is now disputed; and the prevalence of supposed use in the early Church is now disputed. Nonetheless many, maybe even most, priests are still of the opinion that the Roman Canon is a cumbersome bit of Romanitas that needs to be done away with.
Another issue was Orientalism, which went hand in hand with primitivism. It was believed that eastern Churches had stayed truer to early Church practices than western ones, and hence that co-opting eastern elements would promote authenticity in the liturgy. Hence, for instance, one of the big criticisms of the Roman Canon is that it lacks an epiclesis. You will even hear some priests say that transubstantiation occurs at the epiclesis and that the Roman Canon’s lack of the same represents a serious theological defect, and that the Quam oblationem tu Deus represents the remains of an early-Church epiclesis that was hacked out of the Canon later on. As it turns out, though, the epiclesis is a later accretion in the Eastern rites, added later to counter heresies that denied the role of the Holy Spirit in confecting the Eucharist; the Roman rite never dealt with such heresies, hence never had the need to add them.
Plus, the Roman Canon is, in contrast to Eastern anaphoras, highly… well, Roman. That means its legalistic, and modern minds hate legalism (even as they insist on legal positivism). Fr. Hunwicke has some excellent observations of the legalistic structure of the Roman Canon which you can google later.
FInally there is, as you suggest, some run-of-the-mill animus toward traditional practices no doubt at work, too.
Not quite. EPII is inspired by what is sometimes called the Anaphora of Apostolic Tradition. It’s not the Anaphora itself but a redaction of it; EPII is a new composition. Whether or not the Anaphora of Apostolic Tradition is, in fact, of Apostolic Tradition is another question entirely. Some dispute it, hence it is sometimes attributed, not to Hippolytus, but to pseudo-Hippolytus.