On a technical level you're right, of course. But the industry is more concerned with how content is delivered to non software savvy people (the vast majority).

On a technical level you're right, of course. But the industry is more concerned with how content is delivered to non software savvy people (the vast majority). So controlling the tools leads to less overall downloads (in theory anyways.) They'd probably have the same issue if youtube added a "download as audio" button to every video without paying studios.