First off spending more on marketing than R&D is bullshit. That's only true if you add up S&GA which encompasses a lot more than just marketing.

Second, marketing is costly since a lot of it is done in person. Hiring thousands of sales reps doesn't come cheap. It's not due to DTC commercials since only a small number of products actually have those.

Finally, you don't market something unless you bring in more money than you spend. So marketing pays for itself.