You missed the point. Selling an operating system at all was the innovation, rather than having it just come with the hardware. That the operating system they came up with the crazy idea to sell was someone else’s operating system is just an implementation detail, following the age old pattern of stealing others’ work industrialized decades earlier by Thomas Edison and thus requiring no innovation at all.
CP/M was already for sale for years, and the PC DOS that Microsoft bought was modelled after CP/M