Are duct tape manufacturers and their investors constantly hyping about how duct tape is the future, and how it is making professional plumbing obsolete?

I assume you haven't seen those advertisements where they put duct tapes on everything and present it as a universal solution, also there will always be a hype about something in this world and that is not an excuse to jump on the bandwagon unless you're braindead

You assume correctly. I have never seen such advertisements.