Maybe I'm at a disconnect, but the amount of reading time for 3rd years isn't that bad to begin with. Like you said, maybe it's an experience thing, or maybe I'm having early dementia 😳
It's much less as a 3rd year compared to 1st and 2nd, that I believe everyone can agree on. Which is one thing I liked about rotations, depending on downtime, you can go home and not worry about studying. After all, after a day of rotations, it's overkill to go home and read for 4-5 hours...unless it's like the week of the exam or something. 6 weeks for OB for example is more than enough time to get through Blueprints in one pass and be ok for the shelf.
However, calvin, I see where you are coming from in terms of needing to study to pass/honor a rotation which is based on a shelf. That feeling can suck. I'm not sure which rotations you've done, but a lot of services give you time during the day where you can get through some reading. IM for example has a lot of info to know, but there will be time to read all of it, trust me. I thought I would never finish Step Up to medicine but found that I was able to do so just fine. Same feeling with most of my peers.
Utilize your downtime wisely! Be active and involved in rotations, but when your resident says you can go read something for a bit, do it! It's not a trick or a test, when residents tell you to go read, they are basically saying "Yeah, we have nothing for you. You can stand and watch me do discharge paperwork, or do something productive".