I completely agree with you. Routine is important and the first half hour of walking is usually trash, the real important thinking and debriefing happens in the 2nd half hour. I don't listen to podcasts or wear headphones anymore to get there sooner.
We're building a metaverse for knowledge workers with a default approach of "use the physics engine, not magic" when moving around objects - be they virtual robots, sticky notes or walls. Simulating the seemingly annoying, tedious, mundane logistical act of moving through space seems to have genuine benefits in terms of how you think, what rituals you undertake (big and small/collectively or individually), and who you bump into.
Maybe it's not utterly ridiculous that in the future your first few minutes clocked into a virtual environment will just be getting to your workspace. Or I could just have overly fond memories of the Half Life opening sequence https://www.youtube.com/watch?v=Nw63pZcBJH8
Maybe part of what did it for you was motion and changing physical scenery. Maybe lack of control, knowing you had to ride all the way, uninterrupted, had something to do with it. Maybe it had to do with introducing strangers to your environment. And I'm sure there are more possible factors that helped you mentally decompress.
And while it certainly is beneficial to not have a long commute, I didn't realize that I had inadvertently created a daily ritual for myself. During my train rides, I'd zone out and listen to podcasts while watching the surrounding scenery. It allowed me to decompress, focus on something else, and transition out of my work brain.
I love working remote, but I have to admit that I miss that part of my day. I've tried to do things like biking or a treadmill with earphones in, but it's not the same.