What term refers to the rise of a style of rock from a small, regional underground scene up to mainstream pop culture and then the style's subsequent retreat?

This is referred to as a Popularity Arc.

It is a musical term that means the rise and fall of a style's popularity though a stage of commercial boom (mainstream popularity) and then once the popularity dies down the style then retreats back into it's underground state or sometimes disappears completely.  

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trade regulation is a field of law, often bracketed with antitrust (as in the phrase “antitrust and trade regulation law”), including government regulation of unfair methods of competition and unfair or deceptive business acts or practices. antitrust law is often considered a subset of trade regulation law. franchise and distribution law, consumer protection law, and advertising law are sometimes considered parts of trade regulation law.

in general the theory of economics says that the more open to trade a country is the better   the result for the same country and the whole economies.

in real life countries impose taxes, quotas, etc which is not so good for the economies.

this kind of commercial war between the usa and china is slowing down the growth of the whole world so we can say that it is a draw back of trade regulations. and the free trade agreements are benefits of trade regulations.