I do not believe that you (or anyone) can reliably distinguish in a blind test the average $10 bottle from the average $20 bottle.

I think that could be true for for averages, but I usually don’t drink randomly selected wines. I pick wines I am familiar with and like. I think that I can find more wines I like at 20

You should google sommelier tests - they can name regions in blind tests, not just quality.

Whether it’s actually “better” in any real sense is debatable. But wines are certainly distinguishable

Most of us aren't sommeliers though. In a blind test the best I could do would be to say "I like that one, don't like this other one etc". And I feel I know a reasonable bit about reds and have done plenty of tastings over the years. I usually go for the best bang for the buck, and at the moment there's a bunch of great South American wines priced at around GBP5.50-7.00 that are great daily drivers.

Is it quality they can't identify, or price? Is there even an objective measure of wine quality? Price at least is objective.

Quality is inherently subjective, but there are widely adopted rating systems

Costco. Both the cab & pinot grigio are decent- and I have hated every other boxed wine I’ve tried.

Thanks, will check it out!

So if you are looking for something nice and reasonable I cannot recommend enough going to Trader Joes and just trying every bottle under $12. There are some pretty dang good ones.

We tried all the various boxes and found ones we like (bota maybe - the wife buys it), mainly white wines. They seem to keep in the refrigerator fine for a couple of weeks.

Haven't really found a box/bag red that I like enough to keep buying. Instead I keep a bottle of some sort of red on hand so I can have a 1/2 glass with whatever food I cook that night.

Additionally, I order cases of more unique wines from b21 and keep it on hand for special occasions.

Sadly I didn't keep any notes on the producers or grapes. I trust my pals not to bring back cheek puckering bags of vinegar :) Also these are 10 litre duty-free boxes which the equivalents would be eye wateringly expensive in the UK due to the tax our government slaps on wine. So I have to wait until their next trip (who knows when?) for another lot.

I drink a lot of wine, I love buying Yalumba/Winesmith Shiraz casks. Taste great and no ill effects.