I think everyone hopes/hoped for a sane and useful version of modules, one that would provide substantial improvements to compilation speed and make things like packaging libraries and dealing with dependencies a lot more sane.

The version of modules that got standardized is anything but that. It's an incredibly convoluted mess that requires an enormous amount of effort for little benefit.

> It's an incredibly convoluted mess that requires an enormous amount of effort for little benefit.

I'd say C++ as a whole is a complete mess. While it's powerful (including OOP), it's complicated and inconsistent language with a lot of historical baggage (40+ years). That's why people and companies still search for (or even already use) viable replacements for C++, such as Rust, Zig, etc.