Yes, there always has been. The first Thor movie is bad. The second one is even worse. Iron Man 2 was the victim of a lot of behind the scenes nonsense and Micky Rourke being insane and suffered for it. Weak quality isn't new, it's been there since the early days.
What IS new is the machine gun burst of content that has happened since Endgame. It makes the inferior stuff stand out all the more when it's coming more frequently and in greater numbers. Perception is reality, and right now the perception is Marvel has flooded the market with more content of questionable quality than good stuff.