Hardware

That's where the focus comes in - AMD have CPUs, FPGAs, networking, consoles etc. all split between "About the same number of engineers". Nvidia have GPUs, and a bit of Tegra SoCs on the side?

And having more money means you can pay other people to do stuff, be it contractors (so not in the "employee count", or other companies like getting first dibs at TSMC. Though it seems Apple are the ones paying for #1 there right now. Nvidia outspend AMD in R&D in total even then. If they wanted to (and not get slapped down by antitrust laws pretty quickly) they could probably sell GPUs at a loss and just starve out AMD - hell people here will likely celebrate that as they'll get cheaper GPUs from those loss leaders and miss the long-term ramifications.

And the moat is bigger than just internal engineering - if you're a gamedev and you can choose a technique that works better on NVidia, or one that works better on AMD, you'll choose the 90% of your market every time.

When Microsoft are asking around for things to do in the next generation directX, who do you think they'll listen to more?