I think that kind of budget is split behind a LOT of different projects.
They have a roster of ace directors who've done work - Alex 'Ex Machina' Garland did Annihilation, Paul 'Bourne' Greengrass did 22 July, David 'Hell and High Water' McKenzie did Outlaw King, Alfonso 'Gravity' Cuaron did Roma, Gareth 'The Raid' Evans did The Apostle, Jeremy 'Blue Ruin' Saulnier did Hold the Dark, and Duncan 'Moon' Jones did Mute.
I don't think the issue is the directors, but perhaps the 'streamlined' production process. There are more checks and balances involved in a mainstream theatrical release before they finally hit the Big Screen. From length of film dictated by number of showings putting more pressure on having critical editing, to the lack of test audience impact (no reshoots here!), there are plusses and minuses as, whilst we don't end up with The Predator, the end results still often smack of indulgent filmmaking.
There are several of these that actually look and feel like 'perfected' theatrical quality movies (Annihilation and Roma are just two, but most of the above work pretty well on that front, with only Jones' Mute standing out due to appalling editing).
I don't think Spielberg will ever Netflix, and Nolan doesn't make enough films to dedicate years of his life only to see one land on the 'small' screen, but if you need even higher profile directors then this year's giving us Martin Scorsese, teaming up with DeNiro, Pacino, Keitel and Pesci (for the first time working on the same film together), as well as Peter Berg (Lone Survivor) and Mark Wahlberg, Steven Soderbergh (Solaris), and even Michael Bay (!)