Gridbox and Flexbox largely make layouts sane again.
Of course, there are books and guides to help people, but how would someone figure out which guides are worth it? There are a lot of highly rated books on the topic of web development and if you don't already know what you need, it can be daunting.
But yes, flexbox is great.
The same idea may be applied to an operating system's ability to allow a user to operate on their machine.
Edit: It would be useful to consider why the need for a universal interface to the internet was originally sought out.
I think, here, we might looking at it with the wrong lens. I'm unable to find the right words to say this. Let me say this statement feels ungrateful. Web is the largest and fastest growing ecosystem of software we've right now (refer: community size, number of projects on github, say, in Javascipt, CSS, and other web technologies).
You're comparing what is what should've been. By that measure, any human activity will fall short of not only yours but anybody's expectations.
You'd think that getting sane layout control is easy, but apparently it's not. Getting a lot of humans to agree on a fast growing technology is hard (it seems like).
PS: I'm not saying "nothing could've been better, be happy with what you have", not at all. I'm just saying this seems like complaining and a better approach is to try and make it better
I needn't have written up a long tirade for such a simple statement. I see that this is the same sentiment that's espoused by several others in this thread, and thought I'd try and provide a different perspective to look at this with
edit: formatting
Flexbox is essentially an import of those concepts to CSS. There are no new ideas there.
But now flip it around and try to make a beautiful, responsive document in Swing or GTK. The layout managers that make them so great for laying out UIs won't help you much there. They can do it, they have layout managers that operate somewhat like a CSS box flow, but it won't be as natural or as easy.
So it's worth considering if it's easier to evolve HTML towards sane layout management for app-like things, or GUI toolkits towards sane layout management for document-like things.