You're misinformed, I suspect because you are conflating .NET programs being distributed as bytecode with .NET programs being interpreted.

It is true that .NET programs are traditionally distributed as CLR bytecode. This is similar to a .class file or a .pyc file. But the CLR does now, and always has, had a JIT. E.g., the first line or two of https://msdn.microsoft.com/en-us/library/ht8ecch6(v=vs.71).a... , which is for .NET 1.1, which explicitly states that, even at that time, the bytecode is JITed prior to execution.