Mega yachts are not airplanes, computers, software or some other cutting edge or basic research technology. It's a boat that other then adding starlink hasn't meaningfully changed for decades.
Mega yachts are designed using CAD software, the prototypes are milled or even sometimes now 3d printed out of huge foam panel. Advanced hulls are constructed from a number of materials and methods. All of these things required bespoke skilled labor that cannot be replaced with robots or AI.
I think mega yachts are stupid, that doesn't mean they shouldn't exist and to act like they are the same as even 20 years ago is willfully ignorant