30Lb soft pack seems like it would be miserable to carry for a 3 day 45 mile hike.
You are correct; I think I even mention up there somewhere that there is a lot of gear in here I would not really leave in here if I intended to hump it home. Fortunately, I no longer work 45 miles from home (now 12), so it's not as big a deal. Honestly, I don't even have a BOB at the moment, as it all got torn apart to go camping this summer and try out gear.
A BOB for me is a mental exercise; what circumstances am I likely to face, and what gear makes the most sense to deal with them?
I have almost identical GHBs; one in my truck, one in my car. These are meant to support a walk home, with a night outdoors if necessary, even in cold weather. I am building an INCH bag (internal frame pack) with all my really cool outdoor gear that I don't really need for a 12-mile hike home. INCH isn't really a real-world option since a family of four (soon to be five) will either bug in or bug out by minivan.
I have an EDC bag that is functionally my BOB at this point, since it has work materials, tech gear, backups of my vital docs and personal materials, and a small bail-out bag full of stuff for a couple days of wilderness living. I really should get around to doing a write-up of that one...