I don't think you understand the point. You're taking about poor decisions that those companies made several years after Apple and Google entered the market, but ignoring the years long head start that they had and squandered. Why weren't Symbian, BlackBerry OS PalmOS, or Windows Mobile good enough in 2007 to not get obliterated by two brand new platforms?

At some point we have to admit that one of the main reasons for the duopoly is that the rest of the competition wasn't that good.