I applaud you for doing your due diligence.I was going to take issue with what you wrote above. But I decided to do some Googling first so I could have some facts.
I was surprised to find that Bose' revenue was $3.8 billion 2017. Now not all of that is in the home audio/home entertainment business. And they don't really compare to Apple's $229 billion in 2017. But I cede to you that the home audio market is larger that I had envisioned.
Still, Apple is going to have a hard time getting its smart-speaker business to even one-tenth the volume of iPhone sales.
To your point about apples smart speaker business....Apple has zero intention of growing that business to the volume of iPhone. It’s more of an accessory product. It’s about the ecosystem. Hell if Apple just added a fully portable $199 HomePod mini to the mix it could dominate. Since even at half the size it would sound much better than the competition.
I know some will say Siri needs to be better. Which I agree. But for music Siri works just fine 99 percent of the time. And that’s what HomePod is all about. Music.
Personally my opinion on “smart speakers” for all the other random BS is just that...BS. I ask my HomePod to do two things....play music and for the weather in the morning before I leave for work. The rest of it....buying stuff....random facts....I just use my iPhone or iPad.