I suppose it would be hard to lump billionaires in with arbitrary people who generate capital through investments and business, as well as people who do both or just run small businesses. But, I do think software engineering is a working class job. For a long time it's been awkward to say it, because yes it can be extremely lucrative compared to any given other career, but yet unless you're very lucky, it's a path that doesn't excape the drudgery of whatever else you could be doing.
I put my best effort into waking up for bullshit 6am scrum meetings with my global team a few times a week, eventually with the constant stress of some bug being discovered and having to hold for the next sprint and dreading 1-on-1s with this asshole manager who'd consume the entire time with me having to justify why I "wasn't coding faster"; eventually getting laid off during the worst downturn in the tech job market I've ever seen.