MS also used to optimize DOS in ways that clearly hurt their competitors. We've seen Intel aggressively optimize their compiler to slow down AMD... I am sure people have been "optimizing" in such ways for as long as there have been people.
Name a feature that Firefox doesn't have that prevents people from using the web. I can't. But I can name several that I've seen work more correctly on Chrome because they have the resources to make it work in the context of very complicated and legacy-filled rendering engines (flexbox comes to mind) where Mozilla appears to not (ask me about my favorite Firefox-only flex performance issues... To their credit, they have all been fixed, but FF spent a lot of time behind the curve).
Are you saying that there are people at Google whose job description is to tweak Google web products to perform worse on Firefox, just so Chrome appears better in comparison?