There’s cases where it’s easy to determine where to invest product development dollars. In a mature, commodity product we can gain sales through marketing. For a product that stands out we can invest in unique and/or better design which becomes its own marketing.
And then there’s borderline cases. Recently Hershey extended its Kisses product line to compete with M&Ms. If you’re the product manager charged with making this happen, where do you put your money? You might do ethnographic research and find a whole new way to design chocolate kisses. Or you might hire some brilliant product minds to dream up completely novel ideas. Or you might just take a technique that has worked for another product — like filling it with caramel — and invest the money in marketing. Each approach has it’s pros and cons, but the choice isn’t so clear.