I get what you are saying about the price premium. I'm saying there are simple instant / tankless heaters that are simple that cost WAY less than what you are talking about.
Mine is an AQUAH, 10 L,2.65 GPM
There are a lot of other similar ones of different brands around the same cost - $100-$600
NATURAL GAS TANKLESS WATER HEATER | eBay
This is the same or
less than buying a new tank water heater costs.
So you save money upfront AND use less gas.
What I am asking is why would anyone want to buy a $4000 tankless when you can buy a $400 tankless?