I'm not sure what you mean by menial coding but all my employers have supported this in the past. This was a variety of companies, big tech, startups, etc. I think its more likely your employer is the outlier.
No company I’ve worked at has ever had dedicated time for reading papers or articles
Maybe I’ve only worked at outliers?
We also often played board games. My favourite was playing secret Hitler with my team that one time. That was fun! (I managed to become "untouchable" while also being Hitler. That's a memorable moment!)
What I meant with "menial coding" is those jobs where people have to submit TPS reports on how much hours they spend for each customer. Reading a paper such as this one [1] is typically not directly necessary for being a good frontend developer, but it might stimulate someone to develop into a more fruitful employee in the long run. Managers would have to explain to their customer why time is being spent on that, and that requires some vision and creativity, which is not always a given.
One company had a +1 day. You worked 4 days, had 1 day for learning - everything relevant for the job was fine.