I think part of the problem is that there is a lot of theological insecurity out there, so there is a desire to find stability and safe-haven in a bulwark of theological enterprise that has time and development behind it. The problem with that approach, though, is 
that time isn’t God. A major aspect of the incarnation of God in Christ is the Revelation that God’s stability is filial and vulnerable. There is a sense of vulnerability and nakedness before God that characterizes God’s relationship with us, and thus ours with Him. Attempting to find repose in the God who isn’t just a Lion, but a Lamb crucified, doesn’t always seem that inviting to those who are pressed here and there by the polemical winds of mass theological confusion out there. So, for some Protestants, Reformed or Lutheran orthodoxy seems inviting, even if the theological proper foundation behind said orthodoxy is philosophically based (Thomist-Aristotelian-Scotist) rather than genuinely biblically based.
But this betrays the supposed formal principle of at least the Reformed iteration of reformational theology: i.e., the Scripture Principle. People can claim that the refuge they’ve found in some form of Protestant orthodoxy is indeed “biblical,” but when in fact the characteristics of said biblicism have been sublimated by an actus purus god, can it really be said any type of sound, biblical stability has been found? It seems to me a sense of history, time, and an ostensible Divine Providence, therein, has become the refuge; more so than the God who has Self-revealed Himself, His character in the cruciform shaped God that He indeed is.