For most of the hardcore fans who go to see these films 2, 3, 4 times Disney plus meant they could go to theaters then order at home or just order at home and save a ton which is the first thing to consider.
Secondly this movie in the larger MCU is weird. It was never going to be End Game big like a lot of these writers allude to. Black Panther and Captain Marvel were the largest domestic openings for a single hero debut, and they had a lot going for them. Black Panther was just excellent and had a cultural movement. Captain Marvel her placement in the release order leading up to End Game and benefited from all they hype and thirst at the time. BW was released after the IFW/EG hype and set before it. We know Nat's going to live so it needed to setup some much bigger items in the universe and on the surface of things we don't see much of that. Also it wasn't a top tier MCU film. Most of the rankings in the MCU ranking thread even put it middle of the road. So we should expect it will perform like one of the top tier films. Instead we should expect closer to DrS or Ant Man.
Given that this movie as it currently stands is more like a bridge between CW and IFW and didn't push the narrative much, where even FatWS, WV, and Loki pushed the narrative forward, and also given the Disney plus same time release none of the second week results are all that surprising.
Also this doesn't mean that we're burnt out on Marvel. It means we want better.