And AMD has economy of...not having >100,000 employees, multiple foundries, a huge range of product lines, AND also has a CPU architecture that should be MUCH cheaper to produce at scale.
Your simple understanding of economics runs into the fact that the details really do matter, and you don't know any of them.
For example: Can Intel produce their 2 x 28-core Xeon monstrosity for less than AMD makes a 64-core chiplet-based Epyc? And will anybody buy it, when the Epyc is so much more efficient?
Economies of scale or not, that's gonna be pretty tough, and it makes all the difference in the world to your "Intel can just sell at cost" claim.
Not to mention the legal issues!
Unless everybody at both AMD and every FTC-equivalent regulatory agency somehow forgets the last few decades of anti-competitive behavior, Intel can't just start selling their $10k server chips for peanuts.