As i mentioned those cost are real for small public companies, and while potentially tens of millions a year for large ones its a rounding error for them (e.g. MSFT spent ~$80m/yr on Deloitte the past couple of years for audit work, let's assume it also cost MSFT another $80m/yr on internal support for an annual cost of $160m) that would 0.15% of their net income and meaningless number in relation to the liquidity provided to the ~$3t worth of equity holders by being public. Also I'm not sure going to half year would meaning fully change that number a lot, $130m? the audit is annual with limited review of quarterly financials so there is not a ton of savings

Having to do it more and more frequently means more and more of it gets automated.