Bootstrap is useless except for simple static websites. I am not here to start a flame war but I think Bootstrap has no future unless for beginners and very simple projects. For jQuery based frameworks, I recommend Semantic UI.
Most people use Bootstrap and Foundation completely wrong. They're meant as RAD (Rapid Application Development) frameworks, not production-level frameworks.
For example (using Foundation because I'm more familiar with it), you should never have a `div` with the classes `small-12 medium-6 columns`. That's what you do during prototyping. For production, your `div` will have a class like `main_cta` and in your SASS you are calling Foundation's grid mixin.
Production sites shouldn't include anything not being used, which is why libraries like Foundation have discrete components. You only include the ones you need (both CSS and JS), with the assumption that you are doing your own minifying and combining or whatever.
To be fair, if everybody took a little bit of time learning basic CSS nobody would need bootstrap either, especially when rendering differences between modern browsers hardly exist AND the fact that bootstrap doesn't support older browsers anymore.
Momentum is a pretty powerful thing.
And at the end of the day, ALL of these frameworks are pretty much limited crutches for appdevs who aren't that great with CSS. They have more in common than they have separating them.
I tend to rank these things on a balance... of having the functionality that I'm likely to use, versus simplicity and learning curve of the functionality that's there.
So I like UIkit for side projects because it has a lot of built-in components that Bootstrap makes me find external plugins for (e.g. datepicker), and doesn't have a lot of Bootstrap crap that I never use (e.g. jumbotron, wells). It looks great, doesn't have any kind of complex "build system", and takes a few hours to learn. If I wrote a webapp that turns into the next big thing, then I'd have a real web designer redo the static stuff anyway.
How about removing SUI's jQuery dependency? [1] :)
Replacing a 100KB jQuery dependency with a 500KB React dependency I'd hardly call a solution. What happens when the next big thing hits JS land? As it stands the SUI author refuses to refactor out the jQuery dependency due to the amount of work involved.
I guess most websites are "very simple projects" for your standards. Not everyone codes full fledged JS applications with whatever you do. I am certainly not a beginner and I like BS and I think it still has a very bright future ahead. BS 4.0 is the prefect framework for the average modern website. I am sure Foundation and other Frameworks are great as well, I actually never really compared. BSs devteam is highly active and the amount of exposure it gets and the fact that I know how it works makes me stick with it.