That might not be so terrible. GP was suggesting it was due to cost, which is a "run away like the building was on fire" signal, IMO.
If all management knows is powerpoint, that's what they should use to communicate their ideas. It's no different than if all they knew was a napkin and pencil sketch.
I is due to cost. I am aware of a few projects that were done with trial versions of the software stack, almost all the way up to a few months before delivery date.
When Photoshop is too expensive, we get Powerpoint-driven development instead.