I presume yout destroy 5 plus year old tires you have on your car, truck, trailer, bicycle, lawnmower and so on as well.
Can really compare all those other tire applications to a motorcycle/scooter, having a tire failure on any of those vehicles is less likely to be life threatening, especially in a 4-wheel vehicle, but yes rubber is rubber they are subject to " Similar standard for aging ", more so if tire sees little use. IAC on normally driven vehicles tires will wear way before they age out, not so on most "Sunday" driven motorcycles. A good indicator of tire rubber aging out (besides exterior condition) is the constant loss of air pressure, rubber has hardened, does not seal good on rim or osmosis thru the rubber itself. A loss of 3-5psi in a month is normal, more than that
I come from a profession/culture of preventive maintenance (Aviation), even at that level maintenance, rare failures occur. I've seen the carnage and lost $$$$ a blown tire can do, simply by someone not checking/servicing tires
Benjamin Franklin: “An ounce of prevention is worth a pound of cure.”
Don't forget about the spare tire for your car, truck, trailer, etc.
The aging out of a normal size spare tire is 7-10 years, depending on where/how they are stored !!, is similar for compact spares (which are "One time use only", limited on speed/distance and usually flat when you need it !!

)
BTW when buying tires from anyone ask for the DOM, most big suppliers will have this info on hand, sometimes ebay sellers, will resell NOS tires they buy at discount, etc., be careful. IAC, I would not buy a tire over a year old from DOM.
Another BTW, both my scooters have shinko tires and no issues(B400+SW600)