I wasn't there, but my understanding is that essentially all programming in 1971 was done in large corporate settings or universities/research institutions. Those are environments where it's rare for any individual (even someone nominally in charge of a project) to have full creative and technical control over something, and even when they do, it only lasts as long as the project/grant or until their employer puts them on something else.
Compared to the 70s there are effectively no barriers to a passionate engineer starting their own software project as either an open source project or in their own startup, and I'd argue that those are settings where it's actually highly beneficial to bring ego into programming. It's pretty much the same notion as "founder mode" or why BDFL is one of the most popular forms of governance for FOSS.
Personally I'd recommend anybody who "brings ego" to their dayjob to take a stab at FOSS or a startup rather than trying to fit a square peg (caring a lot about their work) into a round hole (the realities of working on large projects).