No, Zerodha does not offer different brokerage structures based on your trading volumes. The charges remain the same for all clients regardless of how much you trade.
Why brokerage rates remain unchanged
Zerodha's choice to keep brokerage rates unchanged is based on the fundamental nature of the brokerage industry and its reliance on how the market performs and how unpredictable it is.
Even though brokerages can seem like they make a lot of money when the market is doing well, this is not always true. Zerodha acknowledges that its business performance is closely tied to the market's movements and volatility, characterised by a high beta (risk factor).