okay, I was sloppy in my description of ETF mechanics.

but from investor point of view it still works as I described - she goes to market, places bid for ETF shares. Then the process splits as following:

a) if there are sellers in the market she gets her shares from them b) if there are no sellers, market makers will still sell her the ETF shares

then once market maker accumulates enough cash from buyers, he purchases/borrows shares needed for exchange for N creation units from ETF trust.

I don't think market makers just go and create ETF shares without there first being demand for them?