Not quite. The humans are remote to the floor. They just work from anywhere instead of on the trading floor. Obviously, there are many algorithms involved too but lots of people still around. 9/1/16
There used to be a time when you could only transact on the floor of an exchange. They had to adapt the rules with advances in technology to allow staff to trade from anywhere. 9/1/16
I don't think that there are fewer jobs as a result. But the jobs are higher end. In the city they expect you to have a scientific PhD that involves some kind of statistical analysis and they expect you to program algos using one of the modern programming languages. These are very highly paid jobs. Also they have created many new jobs that are associated with analyzing the markets and figuring out new algos. It has become much more sophisticated than plain execution which is why instruments move about a whole lot more than they used to. 9/2/16