I don't think this is a fair comparison - 90s and even early 2000s were extremely different from modern devices - JVM was far worse performance wise which matte

I don't think this is a fair comparison - 90s and even early 2000s were extremely different from modern devices - JVM was far worse performance wise which mattered even more because hardware was significantly slower with much less RAM, internet was slow and not ubiquitous. New JavaFX looked promising but it has it's own technical problems + it's developed by Oracle - I don't think I need to say more. Right now I think most platforms support some form of sandboxed app model - all we need is a portable framework that can target all of them exposing a shared API but still allowing native access where needed with decent performance. .NET/CoreCLR could be one such platform, JVM another. C++/Qt tries to be this but honestly it's C++ - it's one of the few technologies where I'd say I'm more productive with HTML5 stack. Rust/Servo could also deliver something similar down the road - maybe you could cut out a "fast" subset of CSS layout and DOM from servo (I'm guessing there are edge cases that make the rendering/layout hard/impossible to optimize) and have something that looks like web stack (could even be a strict subset) but is capable of doing 60 FPS GUI and at the same time can talk to the native code which can then use app/sandbox APIs.