>>12442894Because of the expense. It's the worst of everything in maintenance. You have to deal with salt water and airplane maintenance levels that are already a nightmare. They are loud as shit and very uncomfortable compared to any kind of luxury jet that the high end market would be used to. The only advantage is being able to go to poor countries that don't have any of the enmities that rich people actually want.
If you can afford to rent a corporate jet or keep one on standby why the fuck would you ever want a flying boat instead? It's many times the expense for less versatility.