There are plenty of talented C++ programmers. They just don't want to be abused by trading firms or work in that culture. Even paying them more won't work, because no amount of money is worth that abuse. I interviewed at a trading firm once, while I was working at Netflix (because Netflix encouraged us to interview for outside jobs at least once a year). The comp would have been double my Netflix salary. But I would…
If you're doing general quant library or low latency stuff at an IB I wouldn't say this wouldn't happen but I'd say it's definitely not common.