I find that article very strange considering not one month later, Shinobi confirmed that PS5 games are in development. This happened when everyone got mad that Sony was only showing 4 games at E3.
It's worth noting that Jason's article was published on April 10th, and notes that he spent the past month (March) interviewing people. He also has this quote:
In summary: There is information about the PlayStation 5 floating around at both first- and third-party companies, but it's far more limited than it would be if the console's release was imminent.
Which seems to suggest he had one first party, and one third party contact that knew of Sony's plans for the PS5. (He previously noted that only two people out of dozens knew of the PS5 plans) As his article focused on the hardware, and he wrote a book about how tumultuous game development can be, I don't blame him for not drawing attention to the software side. It doesn't suggest that he hasn't heard of PS5 games being in development.