Probably it's harder than you think to make a cylinder sound that good, plus Siri will do more over time. We'll see if it's a "dumb business move" to control the whole stack. It's worked out kind of ok for them so far.
In the "connected appliance" market, I believe openness is key.
You will definitely know more people who own echoes than HomePods, at least for awhile. Echoes are cheap. Doesn’t mean it’s a “dumb business move” for Apple.