Not to get all Beavis and Butt-head about it, but bad shows suck because, well, they suck, not because they are insufficiently episodic in structure. This is why calls from the critical community, leading many of the fan conversations on these shows, to eschew unified, serialized storytelling in favor of tight arcs and standalone episodes feel like a misdiagnosis. For one thing, they fail to consider that noticeably self-contained installments of series like Game of Thrones and Girls are as memorable as they are precisely because those shows don't usually work that way.
These claims fall into the same trap of cinematically minded showrunners who insist that "it's not TV" by agreeing with them, setting up a false dichotomy between what constitutes the proper use of the medium and what doesn't. In its maturity, television has proven capable of countless things: TV dramas alone can be as densely serialized as The Wire Season 4, as memorably episodic as Mad Men Season 5, as sweeping as Fargo Season 2, and as sensation-driven as Empire Season 1. Sometimes they can be several things at once; Black Mirror, like its groundbreaking antecedent The Twilight Zone, tells a different story with a different set of characters every single episode, making it simultaneously one of the most movie-like and most episodic shows on television. Saying any of these series is closer or farther away from The One True Way to Make TV obscures the fact that there's no such thing.
In fact, this array of options, this wide-open landscape of different structures and tones and techniques, is the truest indicator that "prestige TV" is not a contradiction in terms. Problems with the execution aside -- and problems with the execution is all they really are -- television can do whatever you want it to do at this point, and declaring one approach or the other superior is a procrustean blunder -- like arguing The Godfather is less great a film because you can break it down like a television series, if you're feeling particularly perverse (ahem). If that means some showrunners get to declare their series a double-digit-hour movie, so be it. The proof will be in the pudding, or the cannoli. You can have it both ways. Why wouldn't you want to try?