This is potentially significant for Xamarin apps too (of which Blazor desktop apps will be hosted by). We currently don’t use DI by default but we are evaluating the idea of using Microsoft Extensions in Xamarin for .Net6 to be more consistent with
ASP.NET, and allowing DI as well. Unfortunately early spikes are showing DI causes too great of startup performance hit to enable it (at least by default). In mobile, every millisecond counts and something as seemingly small as 100ms matters to startup time. Using source generators to avoid reflection use for DI and improve performance at runtime would help us enable DI and bring even more .NET ecosystem consistency to Xamarin.