.. XMR could still outperform in this area ..
True, but I'm trying to steer away from speculation, and towards high confidence predictables, to establish a floor for rational value. I was probably too pessimistic about the monetary velocity. I might have been too optimistic about the development velocity, but you haven't convinced me of that yet.
2. Accepting the premise that an XMR economy is necessary, that won't happen in 2015. A reasonably well-run (security-minded, ultra-paranoid) site will have multi-sig escrow, which of course is not available in XMR yet and the website admin will want to see other things in place besides multi-sig such as more liquidity.
Anyone wanting multi-sig could take steps to get it implemented more expeditiously. I don't know of any strong reason to think there will not be a multi-sig implementation in 6 months even without heroic measures, but I'm not really involved so it is an argument from ignorance.
I disagree about liquidity. Liquidity is a problem that will solve itself, just as it was for BTC. A new market will start small, and liquidity will rise dramatically as it becomes known. Even at these dramatic volume lows, plx turns over enough daily to support the liquidity needs of a smallish dark market. And if an operator wanted to add liquidity, they could easily arrange it by talking to large holders.