Imagine you are a C# programmer just as C# 1.0 is released. C# is a fairly simple language at that time (and similar to other languages you already know), so you can get caught up on it fairly easily and quickly. A few years later, C# 2.0 comes out. It's got a handful of features, but not too much for you to absorb. Likewise C# 3.0, 4.0, etc. As long as you stay on the C# train, the rate of new features does not exceed the rate that you can learn them.
Years later, another person comes along and is new to C#, which is now at version 5.0. They are presented with a huge sprawling language and they have to learn nearly all of it at once to deal with codebases they are contributing to. It's a nightmare. They long for a language that's actually, you know simple.
So maybe they find some other newer language, Foo, which is at 1.0. It's small and they learn the whole thing. After a couple of years of happy productive use, they realize they would be a little more happy and productive if Foo had just one or two extra little features. They put in a request. The language team wants happy users so they are happy to oblige. The user is easily able to learn those new features. And maybe some other Foo users want other new things. 2.0 comes out, and they can keep up. They can stay on the train with 3.0, 4.0, etc.
They never explicitly asked for a complex language, but they have one and they're happy, because they've mastered the whole thing over a period of years. They've become part of the problem that bothered them so much years ago.
Fundamentally, the problem is that existing users experience a programming language as the delta between the latest version and the previous one. New users experience a programming language as the total sum of all of its features (perhaps minus features it has in common with other languages you already know). If you assume users can absorb information at a certain fixed rate, it means those two cohorts have very different needs and different experiences.
I don't think there's a silver bullet. The best you can hope for is that a language at 1.0 has as few bad ideas as possible. But no one seems to have perfect skill at that.