I agree. Do it and you'll ask for trouble that could result in your accounts getting banned with all your digital purchases lost in the process.I don't think too many people would want to go for that. It's hassle to switch accounts and I'm betting that breaks ToS.
If you want the flexibility of selling games I recommend buying a console with a digital drive. I do half and half. Some "forever" games like Minecraft are purchased digitally whilst others that I will likely only play through once are purchased on disc.