Other theories of price setting (non-classical and non-marginalist) exist, for example the sample chapter of this book, which describes how the existence and prevalence of markup pricing was discovered independently several times over the past century.

F. Lee, 1998, Post-Keynesian Price Theory

https://assets.cambridge.org/97805213/28708/sample/978052132...

Also see Nicholas Kaldor's Economics Without Equillibrium which can be read in an afternoon.