Actually, you could say we're in the middle of a transition. All the Marvel shows have used one director for the whole season of their shows, and they're not the only ones to have moved on to this format.
As for OP's point, with the series' budget so high, a gun-for-hire TV director might not be accoustemed to the staggering budget they have to manage.
Not one of the Marvel Shows would break any reasonable TV top 10. The "1-2 showrunners, a writers room, and a rotating cast of directors" model is unimpeachably successful; it got us Breaking Bad, The Wire, The Sopranos, Deadwood, The Americans, and Mad Men, among many others.
Atlanta and Barry both have small director pools, being mostly Hiro Murai and the series star/creator. Even those benefit from being able to switch for tonal benefit.
To some extent I think Louie set the precedent there, as CK was given complete creative control. Comedians were asking for "the Louis deal". Glover (and Ansari) seemed to get it, and both had the sense to hire other talented people. Louie (the show) suffers from its self-indulgence to the point it can't be rated that highly, where Atlanta maybe mostly avoids that fate.
Barry has something like 11 writers, and 6 directors, though Berg and Hader direct most of them. Arguably, writing in TV shows is more (or at least equally as) important than direction.
But are those representative of the average 1-2 showrunner outputs? No. They’re not. Most tv sucks. The fact that some shows are not in the top 10 greatest series of all time is irrelevant.
I would say the marvel tv series so far have been pretty solid. Even if you don’t like them because you have an allergic reaction to marvel, their execution has been really good.
If we must talk of THE BEST, then season 1 of American gods on StarZ was the best season of television I’ve ever seen. Mostly all written by Bryan fuller and Michael Greene. Not entirely. How do we weigh this? Hard to say, but man did that show crash and burn when they left.
Most of everything sucks. The point is that the showrunner model, with rotating directors and writers, is the industry norm; it's not some goofy thing Amazon is doing to cut costs.
I saw the first season of American Gods on Starz as well. It did not motivate me to watch the second season. That same year, though, we had The Good Place (showrunner), Better Call Saul (showrunner), The Deuce (showrunner), The Leftovers (showrunner), Maisel (showrunner), and Legion (showrunner). I think the model acquits itself nicely.
They're limited series, effectively just glorified really long movies cut into 6 episodes. They also don't have real showrunners because Kevin Feige calls the shots on overall continuity and vision. It's doubtful that 5-9 season television is ever going to go to this model.
This isn't even true, I went and looked up the directors for Daredevil out of curiousity and each season has a bunch.
Edit: I guess you're referring to the various recent miniseries Marvel has been doing? It's never been uncommon in miniseries, for fairly obvious reasons.
> Actually, you could say we're in the middle of a transition.
I recently noted the same while watching Severance. Almost all of the episodes, barring one or two, were directed by Ben Stiller. I found it one of the best (first) series ever.
As for OP's point, with the series' budget so high, a gun-for-hire TV director might not be accoustemed to the staggering budget they have to manage.