The world running on top of C and Linux being popular have nothing to do with this. Have you looked at what TIOBE claims to measure? They very specifically say it’s not about the number of lines of existing code. It’s supposed to be a measure of the popularity of the language.

From their site (https://www.tiobe.com/tiobe-index/):

“The TIOBE Programming Community index is an indicator of the popularity of programming languages. The index is updated once a month. The ratings are based on the number of skilled engineers world-wide, courses and third party vendors. Popular search engines such as Google, Bing, Yahoo!, Wikipedia, Amazon, YouTube and Baidu are used to calculate the ratings. It is important to note that the TIOBE index is not about the best programming language or the language in which most lines of code have been written.”

C compiled with compilers and standard library written in C++.

My world runs on top of C++.

C is only relevant on constrained embedded hardware and FOSS UNIX clones.