Mostly I’m just wondering how much air these can pump out and how much of it creeps right back in. I would be very interested to note the pressures before and after. There are other considerations as well. Like, sure you’re eliminating some of the oxygen, but you’re also vaporizing some of the wine as a statistical function of the ambient temperature, which is now mingling with what’s left of the air (no, you didn’t make a vacuum in the bottle with something you bought for a sawbuck. I’d be very surprised if the pressure was on the order of 570 Torr) in the bottle in ways it might not have otherwise. Then there’s the issue of how long it takes wine to oxidize with or without some of the air evacuated. I have a bottle right next to me that is over two weeks old left in a dark cool spot that looks and tastes perfectly serviceable. I think that the lack of light and cool location makes a lot more difference than the amount of air in your headspace.
I see a lot of different factors at play. It might be interesting to do some tests and some calculations, but I strongly suspect people are fooling themselves.
