This is what TIOBE have to say this month about the C programming language
The C programming language has a score of 11.303%, which is its lowest score ever since we started the TIOBE index back in 2001. One of the main reasons for this drop is that C is hardly suitable for the booming fields of web and mobile app development. Moreover the C programming language doesn't evolve like the other big languages such as Java, C++ and C#. There is a "new" C11 standard available but this contains only minor changes. The constraint that C object code should remain small and fast doesn't help here. Moreover, adding C++ like features is also out of the picture because that's what C++ is for already. So C is a bit stuck. Yet another reason why C is getting into trouble is that there is no big company promoting the language. Oracle supports Java, Microsoft supports C++, C# and TypeScript, Google supports Java, Python, Go, Dart and JavaScript, Apple promotes Swift and Objective-C, etc. but none of them supports C publicly.
I don't know. Although there may be some truth in what they say, it seems a bit pessimistic to me.
They state that C "doesn't evolve like the other big programming languages" as if that should always be considered to be a problem. There are however be a lot of programs out there written in C, many of them quite old; constantly 'evolving' the language would create backward compatibility issues for a lot of software. The new C11 standard "contains only minor changes"; no doubt because not much needed to be changed!! If it ain't broke...
Worse, the article suggests that one of the reasons for this lack of evolution (stability I would call it) is the '"constraint that C object code should remain small and fast". I'm not entirely sure I would consider this to be a 'constraint'!
The logic of their argument seems to be, taken to the extreme, that the language should constantly change thereby creating backward compatibility issues and, in order to help this along, it should be open to becoming big and slow!
C may well have it's lowest popularity score on the TIOBE Index since 2001 but it is still at number 2 and more popular than all those other languages the article mentions, except Java, which can hardly be described as "getting into trouble". So, neither Microsoft, Google nor Apple supports C. Well, somebody does because it remains at number 2 in the index.
Okay, so C may well not be the most suitable language for mobile and app development and this is a growing area; but C is and remains suitable for many many other tasks: the right tool for the right job...