There was space for both for decades now. There were series that told as one, continous story since Crime Story in the 80s and various mixes of the two kinds like Blake's 7 back in 1978. And that's obviously not mentioning various mini-series reaching way before that. It's just that one format was dominant then and now it's the other.
No, there wasn't. A single show in the late 80s that was cancelled after two seasons, and never got a proper conclusion to its cliffhanger, isn't a good example for this type of show having its space. Why not throw in Twin Peaks as well, there's another show that lasted all of two seasons and didn't get a conclusion until now, when the TV landscape was prime for its return.
Mixing episodic and serialized formats is even worse. It just means that both the episode's plot and the overarching plot will suffer by being squeezed together and having less time to develop.
And mini-series is a whole different thing that has nothing to do with this. They could be made because they'd be 6 episodes long and didn't have to worry about viewers remembering information between seasons. They aren't like episodic shows, and they sure aren't a substitute to serialized shows, which are able to develop characters across multiple seasons, like Breaking Bad, or explore a different socio-political idea, like The Wire.