Andy Rubin left Danger to found Android pretty early after the first couple of Sidekick iterations and took a lot of the brains with him, it stagnated after he left.

Then went on to found Android which was purchase by Google becoming the most widespread Mobile OS. So I would say his track record is pretty good.

You do realize Andy Rubin founded Danger, Inc of Hiptop/T-Mobile Sidekick notoriety. Which honestly was one of, if not the best and most innovative smart phones of that era.