Right, but the Android comparison was meant as a counter example to how packages outside the main repository being difficult to install is somehow a deal breaker to ordinary users. It's not. Desktop computer market share is mainly due to historical reasons.
Of course an easier to use third party packing system would make the desktop easier to use, but that's not where the pain points are. (Especially since most third party binary packaged software is just something you unpack and run.)
Even the most easy to use packaging system you could imagine wouldn't impact the Linux desktop market share measurably.