Is that not because people are generally unwilling to spend money on better solutions and take the path of least resistance?

Way back when, I’d imagine your average micro hifi was more than the average BT speaker someone would buy to stick in the kitchen.

Google home / Alexa on the cheap end, BluOS / Sonos / Heos on the more expensive end all do a great job of bridging that gap. People just don’t bother as it’s not enough of a problem to care about, they don’t have the knowledge (technical or otherwise), or it’s cheaper to use a £50 Bluetooth speaker and done with.