It's kind of ridiculous for a company to 'expect' 50% engineering and 50% people management. It should be fluid and vary depending on the skill level of the team and the complexity and criticality of various projects over time. It shouldn't be fixed at 50% like some magic number.
Agree. For all but the smallest of teams, this just means being both a poor manager and a poor engineer.
Trying to balance this was one of my first mistakes as a manager. I was a roadblock to shipping things because of my limited coding bandwidth, and I wasn't spending enough time focusing on growing people, having career conversations, ensuring my org was structured for success, etc.
Finally putting down the keyboard was the key to me being a much better manager. Yes, I don't have the depth on every framework like I used to, but I still have over 15 years of hands-on-keyboard experience and the "engineering" part of "software engineering" is less about fluency in languages, but more about how to effectively set goals, mitigate impact of external dependencies, design for performance, etc. That knowledge is still very useful.
My hope is that those illustrate the 'spirit of the law' of taking both responsibilities equally serious. An issue is when middle management, so often comprised of literally minded number crunchers, interferes.