There should be a good amount of crossover, but having "specialists" who "own" aspects of a software project has been found, over and over again, to be the most effective way of managing a software team.
Two roles that do not fit into one person's brain are Product Manager and Software Engineer. Should a Software Engineer be knowledgeable about what the Product Manager is doing? Yes. Should the Product Manager be knowledgeable about what the Software Engineer is doing? Yes. Should those roles be merged? Absolutely not.
Product ownership should be left to the Product Managers. Product vision, purpose, and strategy should be available to everyone, and everyone should have a say, but to think that Software Engineers should also do Product Management is ignoring how much work both jobs entail.
I write all of this having actually read the article, and knowing the article doesn't actually say anything I'm disagreeing with here, but I feel it's important enough to say these things anyway.
Software Engineers are in those roles not because they cannot do other roles, but because someone needs to write the software, and writing software is a hard enough job that it's more or less the only thing a Software Engineer should need to focus on. I think people forget that sometimes.