So what you're saying is that all PoC's are guaranteed to take less than a week of work.
What are you even saying? Are you aware that there is a massive range in the scope of projects? You must work on some incredibly simple CRUD apps if this is your take.
These people work mostly in CRUD apps and they're telling you they how feel productive. Btw exploratory ideas even for hard problems come out already after a hackaon of a day or a game jam of 3 days