Doesn’t the act of pouring wine into a smaller bottle to store it expose it to more oxygen in the process?
You are absolutely right that pouring a wine into another container will expose it to air, even if the purpose of pouring the wine is to limit its exposure to air in the long run. But I believe those few seconds of transferring a bottle of wine to a smaller container (with a smaller air-to-wine ratio) are better than hours or days in the original bottle, in which the wine will be sealed in with a much higher volume or oxygen.
I just stood in my kitchen and transferred an entire bottle of wine into another container in 14 seconds. Depending on what kind of funnel you are using it might take a little bit longer, but it’s a few seconds of decanting that could buy you a few days until you’re ready to enjoy the rest of that wine. Now if you’ll excuse me, I think I need to drink this rosé in my water bottle before I need it for the gym in the morning.