C has a large advantage: you can write a compiler in machine language (not assembly, raw machine language) in a week. Not a good compiler: it will produce horrid, unoptimized code. You just need enough to build a good C compiler. From there you can build a c++ compiler, which in turn can build the C++ compiler you want.

Every time you add a new language feature you increase them time to write your bootstrapping compiler. Garbage collection means you will spend a few more months building a garbage collector. (remember we are writing in machine language so most of the abstractions you are used to dealing with - even in assembly - are missing. Thus complexity is growing exponentially)