It varies. GS is ruthlessly efficient. Wall St consultants are seldom inefficient since their contract can be cut any time and their hourly rates can be reduced.
The wall St culture of firing and hiring is, IMO, the most effective driver of headcount efficiency and productivity.
Another factor is competition. Financial sector is rather competitive. The less productive tend to get weeded out.
Many Singapore companies are unproductive, bloated, partly because the need to protect workers’ rights.
Some Chinese private companies are (supposed to be) efficient but the majority is probably less efficient than the developed economies.