Thank you for an excellent post.
In an ideal world we would meet up in Vines to discuss further, but I will give a few thoughts, and some generalisations that I am sure will be challenged !
We now live in the UK, and normally never spend more than £10/ $12 on a bottle of wine from one of the major UK supermarket chains. That gives us options from Chile, Argentina, South Africa, Australia, and obviously Spain, France, Portugal etc. Strangely, there are very few US offerings other than Gallo. Say no more!
I have to say, that when we have been "snow birding" in Florida we have never seen the same range in a store such as Publix.
When on a cruise, chatting in Vines, US cruisers always seem to stick to US wines, rather than exploring other options. (Sorry - just an observation). Perhaps the issue is that they are unaware of other options, and will inevitably opt for Silverado !
We also lived in Spain for 10 years or so, and consequently got accustomed to, how shall I say, a more robust wine when out and about !
Perhaps I am wrong, but for some reason Rioja and Malbec do not seem to be common in the US, but I would happily drink an average Rioja over a good Cab every day !