C is, in fact, bad. The moment it was released. It's so bad that one of the designers of Algol once quipped "Algol60 was an improvement over many of its predecessors, and many of its successors"[1], I had no doubt C was at the forefront of his mind when he said that. It was already a decade old when it was first released. Its wide use is a textbook example of path dependence and fashion worship that plagues software engineering, because it was distributed freely along with Unix, and Unix was the hot new free thing.

GP was just emphasizing how old and crumbling that fossil is with the 50 years old remark.

>What if there's nothing wrong with its intended purpose

And what, exactly, is its intended purpose ? It was to rewrite a 10K LOC kernel maintained by a core team of 3 developers from PDP-7 assembly, in an age before the personal computer and the internet. It was literally created as an ad hoc, bug ridden and unspecified implementation, starting with the thinnest dressing over assembly and adding the absolute bare minimum required for a human to write ~10K LOC without gouging their own eyes off.

There is plenty wrong with it.

>I don't understand the "it's old therefore bad" argument.

It's easy. Fields where there are progress invalidates and supersede their own widsom. You wouldn't go to a doctor trained 50 years ago if you could help it. You wouldn't drive a car made 50 years ago. The only fields where that's not the case is stagnating one, like building houses or making furnitures. Things where 'progress' consists of irrelevant-to-quality changes.

Programming language design is in the first category, and not the second. Especially in the period from 1975 to 2000, it learned and discovered so much that languages made before that period might as well be cave man scribbling on cave walls.

[1] https://quotepark.com/quotes/1741351-c-a-r-hoare-about-algol...