The main problem is that TCC has been "extended" to take on other roles (like linking ELF).
My opinion here is broadly informed by two things, which is that 1) if you want to write a compiler, you should write a compiler, not just tweak an instruction emitter (yes I know that's actually a very common part of the job for working compiler devs, but that's not what you're doing.) And 2) people are far too eager to fall into their old ways even when it isn't productive. A C compiler is comfortable. For someone experienced, it would be easy to port an existing one -- but they probably wouldn't have been asking about it in the first place. For those other people, it's boring and a lot of work when a macro assembler like Forth or Lisp can get you going and writing higher-level code in a few hours. When you're doing things like bringing up silicon you wrote, that's way more important and much more valuable.
You shouldn't eschew things like a C compiler forever if you plan to really get serious. Sometimes you can get one for free (MIPS, RISC-V) and that's super valuable. For a production toolset, it would be absolutely essential. But when you're learning it's easy to sink a lot of time into things like that, when that's not where the real meat and potatoes are.