They’re using “traditional search” to mean the shopping specific search widget or page, which is a separate feature from traditional search. It aggregates retailer listings and sorts them by price.

The AI mode is based on normal top search results, which are oriented toward information about the product like the manufacturer’s page, which is usually going to be full MSRP.

So technically correct that the AI mode is not using the price ranking from the separate shopping mode, but the intent of the AI mode is to find information about the search term first and prices second. The intent of shopping mode is to find lowest prices first and not find any information about the product at all.

In my experience, shopping mode will show a lot of low prices that I can’t actually get because when I get to checkout shipping is $10 higher than anywhere else for some inexplicable reason, or the Google listing was tricked into showing a coupon code that doesn’t work with some exclusion message at checkout. The worst are the sites that show Googlebot a lower price on the indexing pass but then charge regular customers full price when you get there.

In some product areas these tricks are so widespread that every vendor uses them. Search for contact lenses at the lowest price and every single website will have a low price indexed by Google but will add a checkout fee to bring the price back up to full at checkout to cancel out the discount.

I haven’t found shopping mode to actually save me any money other than in a few rare cases. Usually it just wastes my time.

It's not a trick. What you receive as shipping or taxes on google shopping are not the final ones, google doesn't have your full address, neither doesn't have info from the merchant for all taxes (depends on the country) and shipping applied to the product to all possible locations.

Maybe not the same thing you’re seeing, but hiding the margin in shipping fees is a common and time-honored technique on e-commerce sites like Amazon and eBay. Find any regular product, sort by price lowest-to-highest, and witness the number of very cheap items that look like an amazing deal… until you see the shipping charges. At which point it is as or often more expensive than the higher priced items + shipping.

It must be working on some unsuspecting shoppers because those listings are all over the place. There seems to be no policy against them either, and of course those items are never eligible for Prime shipping. To its credit, at least Amazon these days shows you the shipping costs on the product page itself, as opposed to finding out at checkout.