Unfortunately, the web is pretty much captured by google/apple at this point. I don't think it'll be long before gecko and spidermonkey die. When that happens, we are looking at a web that is basically over-fitted for webkit and v8. Which, unfortunately, is exactly what lead us to the bad old days of internet explorer (Ironically now just a webkit skin).
This rhetoric that Mozilla is entirely dependent on Google to survive needs to die because it's completely misleading.
Google is not the only company that will pay for that default search spot, they're just the highest bidder and in the past, other companies have paid the fee (such as yahoo).
Google paid Apple literal billions for the same thing on iOS and nobody is claiming Apple is dependent on Google: both Mozilla and Apple are just happy to take Google's money.
You don't need some big conspiracy to explain what's going on here when the real answer is surprisingly simple: Mozilla is poorly run and it's leaders have repeatedly dropped the ball over and over.