>It would actually indeed be more accurate to quote the difference in assets the donation is causing for you--anything beyond that is arguably being paid by other tax payers.
For tax purposes yes I'm not an accountant but MSFT isn't doing this for a tax break and they'll get credit for the actual financial value of their donation based most likely on their operational costs.
>Your analogy isn't actually analogous. If I take a rock from my back yard and attach a price tag of "ten trillion USD" to it, and then donate it to you, would you accept my claim that I donated assets worth ten trillion USD to you?
My analogy was pretty much correct this isn't an sole actor attributing an arbitrary price, Azure pricing is set by the market not by MSFT.
You can assign a defined discrete value for each "resource credit" for Azure, AWS, DigitalOcean, any other IAAS/PAAS service provider out there based on it's market price as these are defacto commodity resources.
If you give me a rock which is worth a trillion dollars by your account its really not the same thing unless the market agrees that this rock is worth a trillion dollars either in direct value (e.g. you can sell/buy a rock for that sum) or indirect value (e.g. the amount of resources I would need to spend to find a substitute rock).