Most equities trading systems employed today are algorithmic. Today, in 2018, the percentage is probably well over 90%.
But here is an eye opening statistic. Unlike equities, only 10% of FX trades are currently made by EA's. See FX Traders Are Going to Be Hooked on Algos
But the percentage seems to be going up according to the article. And the video in the article concludes by saying coders will be in big demand.
So perhaps the fine men and women on MQL5 should consider that we are at the 2003 spot on the previous equities graph and become masters of the craft.
There is no place to go but UP for FX algorithms and the programmers who make them.
The fact is under 10k USD balance peoples using EA , and actual trade is very simple done by big players
Second big reason opening a lot brokers business regulated on islands they allowed EA's and using MT4 platform