Virtually 100% of the top quants code. From experience, I think your feeling is a close, but a bit off. Some code more than others, some code in pairs with more experienced hardcore devs, but the best all code.
HFT != Banks, Hedge Funds != Proprietary Trading Firm (aka prop shops). They are all in Finance and all could be considered "Wall Street" firms.
Your feeling is akin to thinking the mean annual compensation of all of IT (including software architects in Finance) is the median salary of Junior Windows Administrators :)
Source: I've worked in HFT for the past 10ish years and currently work for one of the larger futures trading firms in the US by volume.
HFT != Banks, Hedge Funds != Proprietary Trading Firm (aka prop shops). They are all in Finance and all could be considered "Wall Street" firms.
Your feeling is akin to thinking the mean annual compensation of all of IT (including software architects in Finance) is the median salary of Junior Windows Administrators :)
Source: I've worked in HFT for the past 10ish years and currently work for one of the larger futures trading firms in the US by volume.