I think you are making a big deal out of nothing: today adoption is tiny but there isn't any coordination problem. Anyone wanting to buy or sell bitcoins, even for very large amount has no problem doing so.

As adoption increases, liquidity (which may be what you allude to when you talk about coordination) will be even better.

I'd also note that facilitating liquity can indeed be a complex problem, but there are people specialized in making money out of it and who therefore have an incentive to continually keep the market liquid, read about "market makers".