In other words, it was set up in a such a way that Channel 4 could not fail. Being funded by the ITV companies if it was a success the ITV companies were quids in. If it failed or ran into financial trouble, well ITV picked up the bill.
The initial funding model had one huge advantage, it ensured that ITV and C4 didn't attempt to compete
against each other for the audience, so the relationship between ITV and C4 was the same as that between BBC 1 and 2.