Sometimes making a decent product is part of making money, but that's never a motivation in itself. We have enough examples showing that if it makes more money to enshittify (and usually it does), then they will gladly enshittify.
I wouldn't say it's just the smart speaker industry.
speakers used to be something that would last a lifetime. I still have the same active monitors that I bought quarter of a century ago when I was producing techno. And I still used those speakers daily for listening to the radio. I used them for a NYE house party. They’re used often and still perform as well today as they do when they were new.
smart speakers is just a way of introducing forced obsolescence into the market.
So these EOL guarantees are nice, but EOL for speaker used to mean 50+ years later or when someone idiot inflicted physical damage onto the hardware. And even then, it was often still repairable.
Every company that makes smart speakers is crooked? Or, the making and selling of smart speakers is inherently unethical?