Thread:VisualEditor/Feedback/Installed Latest VisualEditor (12/14/12) but still uses old editor?/reply (8)

That would be a lovely approach to take (and was what we did initially), but then we found that a number of browsers consistently lie about their ability to support features, or have Quixotic support for core JS language elements such that we cannot write code for the standard and expect it to work on them. For example, Android's native browser in version 2 proudly claims that it supports ContentEditable (the key technology for VisualEditor)… but doesn't actually create a user-editable content area (no trigger to give the user a cursor or keyboard).

I entirely understand your antipathy for browser-based whitelisting, but we do not have the resources right now to manually check each browser on the planet and work out whether it is lying to users about the features it supports.