I think more was at stake than dislike of Veblen. Institutionalism has the nasty slant of (i) looking into actual motives of human actors behind institutional edifices, and (ii) seeing those motives through the lenses of social norms and values. Those nasty tendencies set institutionalism on a head-on collision courses with the official hagiographies that portray upper echelons of the business class as nothing less than efficiency maximizers.
Institutionalism is tantamount to a royal historian describing how the royal family won the throne and by what hook and crook it maintais its hegemony, instead of reproducing the received wisdom that monarchy is a god-given, benevolent institution without which social order would collapse in an instant. No self-respecting court can tolerate such heresies.
Regards,
Wojtek Sokolowski