I'd say it's the inherent foolishness of spending time and $$$ trying to get your web UI into the uncanny valley of looking "as close as possible to the native

I'd say it's the inherent foolishness of spending time and $$$ trying to get your web UI into the uncanny valley of looking "as close as possible to the native UI" instead of spending that time and $$$ actually using the native UI and components, but that's just me.