By that logic Alexa can't lose Amazon any money because it's baked into their products. But in fact, it's a massive money suck. It lost $10B last year, and there's no way you can say Apple magically avoided losses, because Google had similar losses. There is a reason that none of the assistants have really improved as much as you'd expect over a decade+, it's not profitable, and not only that, but it's also -extremely- expensive. Microsoft basically just gave up on it; not really because of market share, but because it made no money, was expensive, and had limited value to customers.
Siri is not why people are buying iPhones, in fact well over 50% of users say they never or rarely use it. So, your point doesn't really hold up. Siri still loses money, just like Google Assistant and Alexa. The apps you listed to compare with OS bundles have not even close to the same overhead as a digital assistant and can be handled with relatively small programming teams.
I love how everyone is missing the point that the assistants lose money. You can subsidize the loss, but it's still not profitable. People do not buy the iPhone because of Siri, especially given it is the worst of the big 3 assistants.
Apple is selling HomePods and iPhones for a profit. But Amazon is/was selling Echos for a loss, in the hope that they would drive additional Prime music subscriptions and lower friction to Amazon purchases. That didn’t happen, and so the product line all-devices-sold-with-Alexa has lost Amazon money. The equivalent comparison, all devices with Siri, has made Apple a ton of money.
Apple's HomePods have been a resounding failure though? I don't know where you're getting your data, but it's wrong. They literally discontinued the original model because sales were SO bad.
Speaking of data, what are you basing that on? They seem to be selling well according to industry reports and companies tend not to continue products which lose money.
Without examining internal Amazon or Apple data on the marginal sales increase estimates for Siri/Alexa it's impossible to say, though.
Apple has earned a lot of money on devices with Siri included. Microsoft has made a lot of money on OSes with Minesweeper included.
It would be wrong to conclude anything about the profitability of Minesweeper based on that fact, just as it is wrong to conclude anything about the profitability of Siri based on the equivalent fact from Apple.
It’s not the complexity of building intents that costs the money. Near real-time speech inference at scale doesn’t come for free. It’s only very recently that has started moving to the edge.