Collaboration all but requires being online (good offline collab is much harder to implement as you surely know), so that eliminates one of the main advantages

Collaboration all but requires being online (good offline collab is much harder to implement as you surely know), so that eliminates one of the main advantages of native apps. Collaboration is also much more useful when you're not limited to only working with people using the same OS. Multi-platform distribution is built into web apps, but it takes a lot more effort to create good native apps on several platforms. Also, of course, no need to install anything on the web, which is important for frictionless collaboration. --- It's no surprise that both desktop and mobile OS-s are very much not optimized for cross platform development. It's a feature (for owners of those OS-s), not a bug.