If they have a laptop with a microphone, they still have the ability to make a much, much more impressive presentation than nearly any of the ones I watched.
Why spend hundreds of hours building your product if you spent 10 minutes writing a script you're going to read out to your webcam in a dimly lit room?
Probably because they are busy growing their businesses in other ways.
As far as I can tell, the distribution of the pitch videos is unknown (and there are hundreds of pitches) so there is no end goal, it seems to be mainly a way of sharpening one's pitch.
Yeah a lot of these pitches were very wooden, and many seemed to try to catch your attention by quoting the multi billion dollar markets the founders wish to grab a piece of the pie from. Shark Tank pitches are way better.
Why spend hundreds of hours building your product if you spent 10 minutes writing a script you're going to read out to your webcam in a dimly lit room?