[throwawaycoder]

I probably can't follow your whole reasoning :-(

I suppose whole sub-economies will emerge. Some will run on Bitcoin, others on dogecoin, others on whatnot. And of course there are markets for exchanging cryptocurrencies. And there will be tools for just accepting any currency, if the salesman doesn't care. For example there is a widget for accepting dogecoins that automatically converts all dogecoins earned into Bitcoins.

Those submarkets will perhaps compete with each other. If few people accept Bitcoin but many accept dogecoin, the price of Bitcoin will fall relative to dogecoin. Or so I imagine.