Got it, you're talking about workers getting ahead as a category -- no objections to that.
I doubt the displaced computers managed to find a better job on average. Probably even their kids were disadvantaged since the parents had fewer options to support their education.
So, who knows if this specific group of people and their descendants ever fully recovered let alone got ahead.
My argument is explicitly not premised on the claim that productivity improvements reliably work out to the benefit of existing workers. It's that practicing commercial software developers are agents of economic productivity, whether anticapitalist developers are happy about that or not, and have really no moral standing to complain about their jobs (or the joy in those jobs) being automated away. That's what increased economic productivity means: more getting done with less labor.
Why should one be entitled to do one thing for their entire career?
The world changes. Those changes cause a need, a job fulfills that need. The world changes again, the need disappears. Why should the job then persist?