You did a very nice and well-controlled study.
Of the inferior methods for wine preservation.
The best method of all is a nitrogen dispenser. After first uncorking the bottle, you insert a stopper/dispenser. Before screwing it down into the neck of the bottle, you let nitrogen bleed into the ullage space for about 10 seconds to displace any remaining oxygen-laden air. You then disconnect the stopper/dispenser from the nitrogen tank and screw it down to form a seal. Then you connect the nitrogen supply again and use the stopper/dispenser to pour out the wine.
Using this method, the wine stays fresh indefinitely. I've left a half-full bottle for a three-week vacation, and come back to find it as fresh as when it was first uncorked.
If you use one of the commercial-style nitrogen tanks, there is also no disposable element involved. When it's empty, you just bring the tank back to your local commercial gas supplier to be refilled or exchanged for a full one.
There IS a disposable element involved if you use the smaller nitrogen canisters aimed at the wine enthusiast market. The initial outlay for a small commercial nitrogen tank is greater than the cost of a disposable canister, but the refill cost for the commercial tank is less, so the break-even point occurs after several refills.
Now I'll be the first to admit that this is also the most expensive of the various wine preservation alternatives. But it also works the best--and doesn't involve expendables.
As to the all the vacuum systems, IMO, compared to a nitrogen dispenser, they suck.
-Paul W.