I myself had a rather similar talk to what that the panelist had with Kitty Hawk people with a very well moneyed, but also very naive CEO of a drone delivery startup. Some sarcasm added, but it went along these lines:
Me: your best bet is to make a helicopter. Men much brighter than you were banging their heads against the wall non-stop for 60 years trying to solve this exact problem.
Startup CEO: But I hired most brilliant engineers from Amazon and Waymo for that. I'm paying them near 200k each.
Me: If this, this, and this thing breaks, your drone drops dead upon an urban area. And if you get into negative gees over ridgelines, your motor don't have enough torque to keep COM behind the centre of aerodynamic forces to prevent inversion. You can't change the law of gravity.
And he was like "can't we really do anything about that, can't we?" These people are so used to the culture of "easy solutions" that it's scary.
A convertoplane this big will be extremely unstable in wind gusts