R&D and marketing department are independent from each other, companies allocate a specific amount for each (often the marketing is much cheaper than R&D) so more money on marketing has no impact on the R&D budget
Are you saying Canon cannot allocate funding between marketing and R&D as they wish?
but if you allocate a team of engineers to improve a video feature on a camera, the same team cannot work on another feature related to stills
If you had the money, you could hire another team of engineers, because:
money and manpower are often the same thing from the company point of view
Precisely. This is however besides the point. I'm sorry I did not explain it sufficiently, so let me repair my mistake by going into more detail:
The thesis is that there is a fixed amount of money available to R&D, and by spending money on video R&D, you are not
spending it on still photography. Therefore, we would get better still photography cameras if Canon focused all
their R&D towards still photography and forgot about video. This is your argument, correct?
But what if the assumption that there's a fixed amount of money available for R&D is wrong? What if Canon actually can afford to spend more
money on R&D if there are more units sold and they make more profit? And then, what if developing video features contributes to more sold units and more profit for Canon? Then the R&D budget would be able to increase
and not remain fixed. The total $$ spent on R&D would increase, and perhaps even the R&D spent on still photography would increase compared to the case when no video features were developed.
I took the example of marketing because it's so obvious (I thought) that they need marketing to sell products. If they took away all the marketing, they would sell very few units (in comparison), and because of that their total budget for R&D would not increase as you would perhaps naively think (because you directed funds from marketing) but would actually decrease (because the total $$ available would decrease).