I think this is a separate problem. The JS ecosystem's love of dependencies is not about complexity, but about "not re-inventing the wheel" - everyone has been trained that for any problem there is a library to solve it, and writing code to solve the problem yourself is a waste of time.
This attitude is already hurting everyone, and it's only going to get worse. But it's a different thing than the complexity problem.
For me it's the definition of complexity. Something that has many parts is complex.
If I want to dig into "how my angular app works", I can't, because I cannot browse 2500 npm packages on github to find out what they are doing. Even answering the question "does my app actually require this dependency" is completely impractical.
To be fair, I had this problem learning Rails too. I like knowing how and why something works, and so the "it just does this because that's the convention for Rails" was confusing and annoying rather than helpful, and trying to dig into the Rails code base to work out why was pointless.
Part of the reason I love Go is because there's no magic. I can look at the definition of a std lib function and it's right there, in plain code, and makes sense.
But despite Go being simpler than Rails (for this reason), I'm not sure that any given Go project is simpler than any given Rails project. The moving parts are more obscure, definitely, but I'm not sure there are more of them or that they're providing more complexity.
This attitude is already hurting everyone, and it's only going to get worse. But it's a different thing than the complexity problem.