I'm not the person who posted this example, but functionally the person who doesn't want to sell their house to a person with less wealth could simply raise the price just as the salesperson selling a car to a rich person. As the person owns that asset, it would be quite challenging to prove because the justification could be that demand justified raising the price.

I'll agree that society has normalized some price discrimination in terms of interest rates being based on credit scores and we can debate the merits in relation to loaning someone money. And there are actually a lot of laws in place around how high an interest rate can be, who can be loaned money, etc.

However, first class tickets are not price discrimination because the offered service is in fact different which means it's not comparable to coach or business. In fact, I'm not aware of a service in which they ask you for your income statement when you walk in the door and then change the price accordingly.

Lastly, I find your rhetoric that a wealthy person should just become poor if they want equal treatment to be odd. Who classifies as wealthy? Will it be up to a judge every time? How will that change as the standard of lower, middle and upper class changes within a country?