I think automation is often a waste of time at the beginning of a project too. Bugs don't cost much (if anything). Building functionality that gets tossed away is routine. Tests don't provide value - getting the code in front of customers and seeing if it's what they really want provides value.

The problem is that once people get used to not having automated tests is can be difficult to build up the habit.

Unit tests are also often hard (if not impossible) to retrofit, although IMO that's a bigger problem with unit tests than it is doing testing at a later stage in the project.