Or Mike Flanagan had a deep love for gothic horror and American Gothic especially and wears that influence on his sleeve. And gothic literature is absolutely steeped in monologues or internal asides.

Honestly if you just fast forward any time James is on screen the back stretch becomes far more watchable. Some of the subplots are pretty hysterical and it produces a some of the most memeable moments in the series. People also forget that it gets way better once they introduce Windam Earl and James leaves.