Why SEBI doesn't slash lot size during high volatility ? why lots are fixed?

I have noticed that we are taking 100% margin with no leverage. This discourages retail traders from trading as capital requirement is high. Why exactly SEBI doesn’t slash lot size during high volatility rather imposes margin requirement? why are lot size so rigidly fixed with no flexibility ? . Things like crude mini , nifty mini are gone but would be way useful during high volatility times like this. It makes more sense to reduce lot size and have margin which actually enforces better risk management and gives confidence to both SEBI and broker that retail trader is not taking much risk. Its way easy keeping number of lots cap than playing with margin requirement.