> To within a rounding error of zero, I don't think anyone outside Windows devs truly expects Microsoft to maintain .NET on other platforms, so it's not really an option in many (most?) fields.
This is provably wrong, unless you want to insist despite the facts because that's what your social bubble tells you to do.
People use Microsoft open source stuff, definitely. It's fairly often decent or better.
But Microsoft's most consistent legacy across its entire existence has been Embrace, Extend, Extinguish. Any Linux-supporting project is directly opposed to their core business, aside from Azure - if it starts becoming a threat, they'll turn it into a way to force people onto their other money-makers.
By this logic we should drop Golang immediately then because tomorrow Google will either kill it or they will add unremovable telemetry that uploads all of your code directly to AdSense.
This is provably wrong, unless you want to insist despite the facts because that's what your social bubble tells you to do.
The most popular deployment target for .NET is Linux: https://dotnet.microsoft.com/en-us/platform/telemetry
Equating whatever else MS is up to with the way .NET evolves and is managed is no different to equating YouTube and Golang.