Is investment banking really worth the time and effort?

When startups raise money or launch IPOs, investment bankers help conduct operations smoothly. After transactions, bankers charge 5-7% commission. It involves buy-side and sell-side roles. Sell-side bankers represent clients selling securities to raise funds. Deals mostly work sell-side, but variable bonuses risk zeroing if deals don't complete. Lucrative job, but ugly if transactions fail.