What? What do you mean by Azure specialists? What do you mean by “run in Azure”? The core of the sim runs on you PC. Sure, some things are downloaded - like terrain textures, terrain models and weather, but I wouldn’t say the sim “runs in Azure”. Far from it.
They started with the FSX code as reference, but it’s a completely new sim. They have just copied some parts over. Flight model is completely new, graphics engine is new, weather engine is new, … They’re definitely very skilled game developers. Azure has nothing to do with it. I’m sure they could have used AWS or GC if they wanted to.