Under these circumstances, it is appropriate to ask who is the customer. Then presume that the company is trying its best to make the customer happy.

Apple has clearly defined that the customer for the "default search engine selection" option is Google and not the users. There is obviously some mediation by regulators in Europe and elsewhere (hence Google's major competitors being included on the list), but the customer is Google. I think that from that fact flows two further inferences: A) the customer might not want to write down everything, or even communicate in any non-deniable way, all of their preferences (due to those regulators), but can presume that Apple understands their preferences B) The customer is happy to the tune of 20 billion dollars with the current set-up.

I can think of 20 billion reasons.

I think the circumstantial evidence is sufficient to figure it out.

Are we supposing that Google made their payment conditional on obfuscating the ability to switch search engines?

Even if not explicitly conditioned, which I don't believe came out as being the case in this case, there's still an inherent motivation. Google will pay more for a default on an OS where it's hard to switch the default than it will for a default where it's easy to switch away. Google might pay $20 billion for defaults on iOS as-is where 99% of people stick with Google, but if Apple started asking users if they were sure and offering alternatives and Google only remained the default for half of people, they logically would only offer maybe $10 billion to remain default on the same actual terms.

It seems plausible. Mostly I think people should be explicit and clear about their accusations.

Something that doesn’t make a ton of sense to me in this theory is that, despite it being hard to add a new engine (which is not great), it is easy to switch away from Google on iOS. And the big search engines are in their pre-populated list. So it seems Google and Apple have engaged in a conspiracy to keep people from switching… just to the niche engines? That doesn’t make a ton of sense, right? Google is probably not more scared of Kagi than Bing.

My first guess is that Apple lived through the era of confused non-technical people adding a bunch of scam search engines and didn’t want a repeat of that.

> That doesn’t make a ton of sense, right? Google is probably not more scared of Kagi than Bing.

Google certainly should be more scared of Kagi than Bing. Bing is a known quantity that's not going to suddenly shoot ahead of them. A smaller, newer competitor might. Just like how it wasn't Lycos or Jeeves that dethroned Yahoo, it was the two guys in a garage.

No, I’m supposing that Apple knows they have more control if they obfuscate the ability to switch. And more control is more valuable to Google or whoever else wants to pony up to be the “default”.

This is one of those "a wink is as good as a nod to a blind person" situations so that plausible deniability is maintained while getting the desired results

I get that sometimes conspiracies are not explicitly written down in contracts. But we can still describe them in clear terms.

As long as it’s an ongoing relationship nothing needs to be said. Apple knows that if more users swap away from the default then the default setting is less valuable.

If that is what the (vaguely described) conspiracy is, it doesn’t really make a ton of sense, because the pre-populated list of search engines already includes most of Google’s main competitors.