Hmmmm then why is there usually a mileage/month expiration on it? must be a conspiracy.
The way I understand it, that supposedly refers to acids that build up in the oil as a by-product of combustion contamination (from blowby, plus all of the little nasties that the oil flushes away from the moving parts) and eventually attack the metal surfaces. If you change to fresh oil just before storing and don't drive the bike, the oil should not have any of those by products, and you should be able to just ride it in the spring without changing it again.
However, if you change the oil, then ride it for 1,000 miles then let it sit for 6 months, theoretically some internal corrosion can occur from the normal contamination.
Personally, I think it's bunk. I restored an old Honda Nighthawk that had sat for 12 years, and when I took the valve covers off, it looked brand new under there. 12-year-old oil didn't cause any corrosion.
The old "3 months or 3,000 miles between oil changes" is for "extreme" service, according to most vehicle manuals (and clever marketing by Jiffy Lube and the like), and 5,000 miles is usually the acceptable range for "normal" driving conditions. I've never seen an expiration stamp on a bottle of fresh oil.
Personally, I just go ahead and change my oil and filter about every 3,000-5,000 miles; it's cheap insurance and changing too often will never cause a problem, except in the pocketbook.