Money can be lost. The trust extended to a gateway should be rationally balanced against the benefits of that trust.

This has only a minimal affect on people who use gateways to facilitate payments -- only money that's "in transit" is at risk. If you figure a respected gateway has, say, a 5% chance of going bankrupt or being shut down in a year and will be holding 5% of your yearly gross at a time, that's functionally equivalent to a .25% cost. Compared to 2% for credit cards, that's wonderful.

However, it can have a significant affect on people who use gateways as a store of value. For that, you really want gateways that are insured. This is a great application for Bitcoins, IMO.