Don't see how that will work, given that a lot of the more desirable apps use native API and their developers have no desire whatsoever to put in more work to a

Don't see how that will work, given that a lot of the more desirable apps use native API and their developers have no desire whatsoever to put in more work to adopt yet another Google OS, in addition to Anrdoid. See e.g. what happened to Windows Mobile. Excellent OS (better than Anrdoid in terms of UX IMO), but failed to get traction with devs. It's not like all Android phones will just cease to exist when Fuchsia comes out. So even if this is done near flawlessly (chances of which are slim given how different Fuchsia promises to be), Google would be expanding the already insane Android testing matrix for devs.