I am often frustrated by PDF issues such as how complicated it is to create one.

But reading the article I realized PDFs have become ubiquitous because of its insistence on backwards compatibility. Maybe for some things it's good to move this slow.

The article is wrong, the PDF spec has introduced breaking changes plenty of times. It’s done slowly and conservatively though, particularly now that the format is an ISO spec.

The PDF format is versioned, and in the past new versions have introduced things like new types of encryption. It’s quite probable that a v1.7 compliant PDF won’t open on a reader app written when v1.3 was the latest standard.