I think there's a misconception there. it's just that they have a minimum amount to buy for you to participate in the ICO. Let's say 0.1 ETH or 0.05 BTC, it really depends on the ICO. But look at it like a fundraiser where when you can't reach the specified goal, the project will not be put into realization unless the company has their products used already and it's just the implementation.
Well, now a days most of the projects are raising enough money for developing their product in the market and it completely depends upon the investors how much they want to invest into the ICO because most of the ICO are accepting from 0.1ETH.