The minimum support price is announced by the central government for twenty-three crops on the recommendation of the Commission for Agricultural Costs and Prices. In practice it operates as a real purchase guarantee for two of them, wheat and paddy, and mainly in two states, Punjab and Haryana.
That is the whole architecture of Punjab's agriculture. Assured purchase at an announced price removed price risk from two crops, and every farmer rationally grew them.
It fed India. Central grain stocks came out of Punjab and Haryana for fifty years and the public distribution system ran on them.
It also locked the state into a cropping pattern that its water cannot support, and the mechanism that would unlock it, procurement of other crops, has never been built.
The demand for a legal guarantee of MSP, which was the unmet demand of the 2020 to 2021 protest, is a demand to extend the guarantee rather than remove it, and the argument about whether that is affordable or wise is the central agricultural policy question in India.
The price is worked out from a cost formula the commission publishes, and the argument about which costs go into it, whether imputed family labour and land rent are counted, is the technical dispute underneath every political one about the level.
That is why the crop pattern will not shift. A farmer who moves out of paddy moves out of the only guaranteed price in the system and into an open market with no floor.
The 2020 laws and the protest that followed were about whether that guarantee would survive. The laws were repealed and the guarantee was not made statutory, so the question is exactly where it was.