I believe there was a deliberate choice to keep DAB quality low to avoid people getting clear digital recordings for piracy.

Subsequently rendered redundant by Napster, but we are stuck with DAB.

That was a factor, but the core was more choice. Broadcast used to be about quality.

It's quantity now, with "just goos enough" translating to what people will tolerate.

Thought experiment for you:

Which do you prefer?

Low quality, but compelling. Or high quality, not so compelling?

That answer is what drives everything. People will take compelling every time. Very few will take quality as a primary factor.

More choice = more opportunity to be more compelling = higher AD rates = more revenue per bit.

Sounds like a recipe to kill radio in favour of higher quality cell data streaming.

It's never higher quality.

In the US everybody wants sub streams so they can sell more commercials. It's all about the money. Thankfully FM is still going strong here.