C gives you a level of control and responsibility not found in other languages. That's a choice, not something that is inherently worse. It may be worse for what you are doing. Most people don't value the level of control that C gives you and would rather chose another language and that is fine. But having a language available with this level of control is valuable, even if few people chose to use it. Most UB in the C standard is there for a very good reason.
You are right, but no language has tried to claim the space of giving the user more control, so C remains the lowest level language we have that is portable. I think there are lots of opportunities in this space, but i don't know of anyone working on it.