Since you are genuinely asking:
There is no other alternative, and I believe it would be a bit unfair to judge a fine dining restaurant based on its a-la-carte or lunch menus, unless that it what it was originally designed for. If there is a lunch or takeout option, it is most likely still a reaction to the pandemic. To really “try” this kind of restaurant, you should go for the full dinner service and experience it.
In my opinion, if $400 is outside your budget or comfort level or calculation in spending for food, then you should simply not go. But to say that $400 amount is “ridiculous” shows that you are out of touch with the realities and economics of fine dining (and the discussion). If the price was absurd to everyone, then it would not exist.
As a relative point, I can say the same thing about quite a few things that I feel are not “worth it,” but I do not go around expressing my disdain in the respective communities out of respect. People visit fine dining restaurants and pay “ridiculous” amounts because they feel that it is worth it, for similar reasons that people drive luxury cars/bags, sit front row at a concert, pay first class for airplane seats, etc…
I do not believe one has to be rich or reckless to prioritize eating good food above other things, and it is tactless to state matters as such. Your lack of respect and boastful ignorance is what people have a hard time stomaching on this board.
To ground this post, I think a more apt and merited discussion on your part would be comparing a $400 meal at Noz to any other sushi-ya that you have been to or want to go to. There is value that can be found in many of the restaurants in Los Angeles, and surely you are paying for the brand at quite a few of the establishments in the city. Noz (when it opens) vs Ginza Onodera vs Shunji vs Kaneyoshi vs Morihiro vs Mori vs Takeda vs etc… would be valid comparisons, in my opinion. The ridiculousness of the price can be established after one has experienced alternatives within the same price range.
Thank you for reading~