Condensation can only occur if warm up / cool down cycles are short. I have always seen the worst thing for an engine is to start it up and only run it for short burts at a time. An engine that only goes a few miles up the road and back to the store a few times a month is in worse shape than one that obtains enough temp to prevent condensation. I had a 400 CI Ford engine in a truck that had a valley pan in between the heads under the intake once. The valley pan had rust underneath it right in the middle. It was the condensation that collected on it and rusted the middle of it out. Royal Purple is synthetic and the materials are not petroleum based. I would think it could sit 3 years easily. If you only drive it 1000 miles a year then why dont you just save yourself a buck and buy regular oil. You wont hurt anything.
I asked this very question to Black Stone Labs, they responded with basically not to worry about oil sitting for long periods of time while in the motor. It takes me 11 months to reach 5000 miles (at least). So since they do my oil testing I asked them about the length of time it takes could the oil start to lose viscosity or just break down in general. They basically said no. So I stopped worrying about it. I run MC 10w30 which is a synthetic blend. Would like to add due to a leaky rear main seal I do have to add a quart in between oil changes.