I bought a crazy expensive Toto when rebuilding the master bathroom because it was advertised to be quiet. Flushing sounded like you were using depth charges. A stream of plumbers, contractors, and sales reps came to look at the installation and eventually decided Toto must have changed something in that model, and swapped it for a mere mortal toilet that won't wake the entire household at night.

Maybe their brand hasn't earned enough credibility to command the prices.