This is more of a question of "why it's not done yet?":

• Mono.Cecil and other dependencies do support netstandard2.0
• There's the .NET 8 tool in the repo which is actually using dependency libs in the netstandard2.0 configuration so it's working and tested
• Codebase is explicitly .NET 9 friendly overall, e.g. removing the BinaryFormatter (the reason I had to revive my involvement in the ilrepack, to be honest, is the BinaryFormatter breaking things)
• .NET environment overall is moving away from netframework, so many (and, with time, most?) of the library consumers will be netstandard and not netframework
• Speaking of specific examples is "dotnet msbuild" which is explicitly not netframework

So, the proposal would be:

• Create a new ILRepack.Lib project in a new folder, using ILRepackTool as a template
• Dual-target net472 and netstandard2.0
• Publish a nuget package out of it