Working hard becomes ... acceptable if you have some sort of individually desirable outcome. That can be results, values - it also can be money.
Working 100 hour weeks for minimum wage as a quasi-appliance? Very few outcomes are worth that. That's 'Factory worker, ca. 1890' territory.
Working 80 hours a week for little pay, but with a goal that supersedes your own ego? Sure, there are people like that. 'Médecins Sans Frontières' come to mind.
Working 60 hour weeks for a small wage, with own agency? Now we are looking at a different equation. That's every small business owner, ever, and most good team leads.
Working 40 hour weeks at a sensible rate, desirable outcomes, taking charge, with agency? People will kick in your door to work for you.
Now add relational positioning ('yeah, my job is bullshit, but I could earn less for more meaningful work'), and it gets chaotic pretty quickly. Humans often sacrifice 'meaning' for being 'ahead of that other guy'. That's why 100k Jira clicking jobs exist with people still being happy about it.
> and another group who earns less, works hard, but does something they find very meaningful and important to their ethics
It is very rare, in my experience, to find this in tech careers. I don't know why - perhaps its something structural about the uses to which technology is put, and the disconnect with personal values and/or work ethic.
2. Tech work is very lonely while requiring communication skills. You sit there all day long staring at the screen, once in a while replying to official-sounding Slack messages from people you wouldn't recognize in real life. In contrast, there are jobs where you're in a small group, and while your hands are busy, there are endless opportunities for conversation.
3. Your effort has zero correlation with reward - the effects of your work are often extremely abstract, especially if you're doing background work that doesn't pump out features, and managers rarely reward effort with salary bumps.