[hywel]

"Most startup failures were caused by building the wrong product, or lacking strong sales skills, or not having a viable business model" <- the first one of these is the biggest cause of startup failure, and is technical.

Startup technical diligence needs to check for a minimum level of ability and beyond that, ability to find the right direction to build in.

The idea that what product you build is not the responsibility of the technical team is almost certainly why you think there's no point in doing technical diligence.