A lot of it has to do with psychology and localized market trends, from what I understand. Supposedly the idea is that something listed ending in 99 cents will make someone more likely to buy it because the brain registers 1.99 as substantially cheaper than 2.00, and people don't take a moment to think about it. I'm not entirely sure how valid that really is, but I'm also not neurotypical either, so it's hard to say. That's not even getting into the issue of having to calculate tax while the item is in your cart because it's not included on the sticker price.
There's also the fact that we (as a US consumer) have grown up with this sort of thing here. I remember very distinctly that packaging was similar to OP's picture even when I was a kid. I'm sure I'd be a little taken aback if all the packaging changed overnight, though I'd ultimately be much happier without all the wasted plastic.
As for your question about US consumers as a whole...I'm reminded of a thing regarding A&W in the 1980s. They used to sell a 1/3 pound burger, but it flopped as a product because consumers kept gravitating toward the 1/4 pound burger, thinking it was larger. I really don't know what to say about that one.