Why aren't price comparison websites big in the US?

Scale.

San Bernardino County California is 1/3 larger than Switzerland. Just a county, not even a state.

Online shopping among only Swiss websites is more or less among local retailers relative to the US.

In the US, I can comparison shop using Google, eBay, Walmart, Amazon because if it is sitting in a warehouse 4000km away, the logistical chain is simple from a regulatory standpoint and there is established logistical infrastructure for its transportation, UPS, USPS, FedEx, and a large number of regional aggregators.

There's no customs declaration, tariffs, etc. The only difference between New York and Texas is sales tax rate.

At an abstract level like the community of nation states, Switzerland and Germany are arguably like the US. In physical reality, they are not transcontinental scale.

Well for the things you mentioned, health insurance and broadband, there's often not a lot of competition here, with only a small handful of choices available in any particular area. Also health insurance is usually either through your employer, who will offer only a limited set of plans or "Obamacare" which is all very complex and differs a lot from state to state and even between locations within a state, but there are government websites for finding plans.

For physical products there's Google Shopping, which will usually get you a pretty good idea of the price ranges for an item. For large items, like cars, I'm sure there are several specific sites for those.

I'm not sure there's a huge unmet need here. Could you give some more examples of how people would use these types of sites ?

EDIT: Also for many products (especially lower cost products) it's hard to beat Amazon's prices and their customer experience is so much better than virtually everyone else's (both online and in terms of how the deliveries are handled) that it's often not worth shopping around much.

> However, there appears to be no one particular dominant one-stop type of portal offering comparisons across all kinds of product and service categories like Comparis or Idealo.

The US market is too large. Comparis works because there are only a small number of competitors in each of their targeted categories; e.g., they're able to maintain a list of current and past mortgage rates by period for almost every Swiss provider. That's much more difficult to do in the states. The same reasoning applies for mobile tariffs, personal loans, and automobiles.

Re healthcare, also remember that most people in the US have health care through their employers, so price shopping isn't necessary. When you do need to purchase private health insurance, most of the states along with the Federal government have health insurance marketplaces that provide their own price comparisons.

Also, competition among price comparison websites is much more intense, so they tend to focus on particular niches. It's easier to, say, run a successful comparison website for a single product category than for a large range of product categories and services. Compare pcpartpicker.com with toppresie.ch. They both have quality content - in fact, I would say that toppreise.ch is better, but the user interface and overall experience is much better with the former.

Another important thing to consider is most of the time in addition to what others have said is that the best price for any given product will usually be at some large retailer (online or otherwise). The key here is MOST of the time. Smaller retailers might have better sales for products, but sometimes they have much worse return policies, or risk going out of business so won't support you if anything goes wrong, and the extra 10 bucks saved isn't worth it. So consumer behavior in the US has essentially learned to focus on the larger national/international retailers. That's why "buy local" is a thing here. People feel that they are somehow supporting their local economy more directly by buying from some local small retailer.

Because of Dark patterns and Javascript. JS makes it hard to scrape unless you have enough processing power to run a browser headless for millions of product websites, and without bombing their sites too hard.

Then there's dark patterns where sites will literally tell you one price on the front page, but then at checkout tack on a ton of fees, and this is only AFTER you sign in, which means your price scraping bot has to have an account for millions of services that implement this pattern.

I don't believe this is something tech can solve, it's a people problem. The only way I can see this being a thing is if the government formalizes it in law or something, where each retailer has to submit the price to some centralized API where consumers can then pull from.