There is no doubt that the developers behind Counterparty are exceptionally talented and the coding may provide incredible utility for accomplishing revolutionary tasks. I was initially extremely attracted to this as a potential investment vehicle (Bryne's plans are impressive), especially since there is no mining and a cap of less than 3 million coins.
However, from an investment standpoint, I have a real problem with getting optimistic about the longer term valuations of Counterparty because 1) all of the code is open source and it can be duplicated & lacks proprietary value; 2) Bitcoin itself could end up adopting these features; 3) a big player like Google could bring yet another coin with all of these features (and much more) which could overtake the dominate role for this space; and 4) there are no guarantees that Bryne's dream of an alternate exchange will be the one that actually gets off the ground with all of the regulatory hurdles and track record of contrary political positioning that has been so unpopular with regulators and Wall St. The scum hate him with a passion. As a result, these factors pose a long term threat to the viability of this coin ever reaching significant value.
I would love to be proven wrong and, thus, provided with a good incentive to invest. But I am afraid that what Counterparty has created for the free market is somewhat similar to what pharmaceutical drug companies would be up against if they ever attempted to patent naturally occurring, unaltered herbs and healing plants as cures for diseases. There is nothing in place to protect the exclusivity or scarcity of this very impressive technology that has been released out into the wild.
What you've laid out is a problem that all cryptocurrencies face because they are open source. I heard it a lot about Bitcoin last year. The banks hate it, they'll never let it thrive. Corporation X will come out with corporate coin. Country Y will come out with Countrycoin. But it hasn't happened yet. The reason is that large corporations are highly centralized, as are governments, and don't work well with the decentralized aspect of cryptocurrencies. No one could trust it implicitly and that defeats the purpose.
Back to your argument... It's a pretty reasonable one, that someone could come along and create a Bitcoin clone with a better marketing and dev team. But then why has Bitcoin not been replaced? There are faster coins with more features and coins with highly capable dev teams, yet most of them languish and eventually become worthless (or close to it).
It comes down to first mover advantage. With a technology that is adopted by such a small percentage of the population, and one that is so nascent and volatile, there just isn't the market for so many altcoins. Therefore, the first usually prevail. DOGE, NXT, NMC, LTC... they are still around because they were the first to offer something different but not necessarily the best. It's difficult to say exactly why certain coins prevail over others, but being the "first to market" is certainly one of the main reasons why they do. That and market liquidity, which follows adoption as traders flock to it.
XCP is the first sidechain. It doesn't use its own blockchain (rather, Bitcoin's) so there's no mining community to add volatility. And it has been chosen by Overstock for a multimillion dollar project, something unprecedented in an altcoin.
As always: high risk, high reward.