> Given many of the API additions in .NET Standard 2.1 require runtime changes in order to be meaningful, .NET Framework 4.8 will remain on .NET Standard 2.0 rather than implement .NET Standard 2.1. .NET Core 3.0 as well as upcoming versions of Xamarin, Mono, and Unity will be updated to implement .NET Standard 2.1.<p>At some point, is it reasonable to expect Xamarin, Mono, Unity, and .NET Core to all really be backed by .NET Core? And if/when so, is there any difference between .NET Standard and .NET Core since, after .NET Framework has been essentially maintenance-mode'd, there will be only one .NET Standard implementation? Similar question, besides just having multiple implementations, what benefit is there to having both Mono and .NET Core separate (at least for the .NET Standard impl part)?