I've noticed a trend lately where items will "ship from the US" with an estimated 2-3 day delivery date only to be delayed at the sender, eventually "ship" a month later, and arrive with international postage a few days afterward. I'd love to filter that kind of crap out as well, but I'm not sure how Amazon could go about actually implementing it.
That's happening on Aliexpress and other places too - I've wondered about this. An aliexpress seller said ships from US, arrives within a 5 days or free, then 1.5 months later it finally arrives and they get dispute overturned because it was delivered. So pathetic. The stupid postage gives away their "shipped from US" game.
Read the fine print, and launch the dispute right away. Oh, and look at the seller's reputation/history.
But maybe I just wasn't affected because I don't even look for locally shipped items, as I'd be better off going to B2B-focused niche retail locations in the rough vicinity.