PR firms don't write articles for legit journalists and they certainly don't pay staff journalists at the reputable publications to write them (not without disclosing them as sponsored content). At most journalist publications sponsored content is handled by an entirely different group (not the editorial team). And journalists get really annoyed if they feel like a company or PR firm is trying to tell them what to write.

A PR firm will help find a story, write a pitch, and package up the details to make the reporter's life easier (studies, data, contact info, etc). They might help with things like vetting the subject or coordinating scheduling for an interview, etc. In this case, even the photos were taken by a staff photographer for the SF Chronicle.

Is the company going to pitch a story on how many ER doctors their scooters are keeping employed because customers injure themselves? Probably not. But it's not their job to and it's certainly not unethical to pitch a positive human interest story.

Anyone can pitch a journalist. That's frequently how they find stories. And it helps if you include information that will make writing about it easier.