Stock trading and software development aren't tasks I'd rate as difficult mental labor.
In fact, the reason such jobs are desirable, is specifically because they're actually kind of cushy.
Stock trading is a task that has been over-complicated mostly because investors need to engage in double-speak, so that motives for trades that lead to financial gain can be sufficiently obfuscated, when explained to auditors, judges, juries and regulatory officials. Behind the curtain of quants, it's really just a lot of grocery shopping.
Software development is mostly about stacking legos in ornate fashion. Bytes cobble together as building blocks. There are a variety of 256 different building blocks. The computers themselves, the syntax of the code, the methodology of data structures and loops, these aren't the hard parts. It's just plumbing.
Plumbing is probably a similar target of automation.