The issue is really that "Usability" in the sense of "helping people achieve their goals" isn't really a priority for most of these vendors. When they talk abou

The issue is really that "Usability" in the sense of "helping people achieve their goals" isn't really a priority for most of these vendors. When they talk about "usability" they really mean: engagement, retention, distinctive branding, and optimising for whatever KPIs are important for their business. Then there are the economic pressures of supporting multiple platforms, so you get shit like Electron and PWA where for a fraction of the price you can present the same semi-usable interface on different platforms - where it looks like your signature style but doesn't look like any other apps on the platform.