Oh dear. Yet another article that reinforces conflicting messages and gives ammunition to whoever wants to be "in charge" of a product.
No. This is not the authoritative model. It's written like this is what the industry has settled on. But you can design whatever model that you want as long as you're clear on "who actually has buck stops here decision making and accountability over those decisions".
For Scrum adherants...
If you are using Scrum (many claim to be using it but are actually using some variant of ScrumFall), there is a Product Owner role who has "buck stops here" responsibility in the team. The PO does a lot of the "Product Manager" (with revenue/KPI responsibility) and "Product Marketing Manager" (positioning/value based on customers) also. If you are going to have separated out people (Prod Mgr, Prod Mkr, PO), you must designate that the PO has the "buck stops here responsibility" in the Scrum team, and relegate the others to stakeholder roles who hold the PO accountable.
For us, we've done away with the separate roles and said that Product Owners are Product Managers. They have "buck stops here" responsibility. Stakeholders hold them to principles by asking challenging questions: "Are you maximizing value?" -> show us the empirical evidence, etc.
>> The Product Manager
>> "These individuals are often referred to as mini CEOs of a product. They conduct customer surveys to figure out the customer’s pain and build solutions to address it. The PM also prioritizes what features are to be built next and prepares and manages a cohesive and digital product roadmap and strategy."
This is the Product Owner role essentially. If you have a separate Product Manager from a Product Owner, they should definitely not prioritize what features should be built next. Maybe at a very high level they are identifying a market need and saying "Hey there's something here, team - next quarter please figure this out". The PO is responsible for the roadmap, backlog and maximizing the value of the work from the Scrum team.
All the Prod Mgr can really do is to be a good stakeholder, do the research, give lots of good external market inputs to the PO and hold the PO accountable for delivering value.
>> The Product Marketing Manager
>> "The PMM communicates vital product value — the “why”, “what” and “when” of a product to intending buyers. He manages the go-to-market strategy/roadmap and also oversees the pricing model of the product. The primary goal of a PMM is to create demand for the products through effective messaging and marketing programs so that the product has a shorter sales cycle and higher revenue."
Yes and no. Because the PO is so close to the product, speaking to customers, getting feedback from customers from rapidly delivering iterations (again, assuming you are using Scrum(TM) correctly, and not the bastardized "scrum" where devs are relegated to code monkeys), the product positioning/messaging/value propositions and pricing model will naturally emerge from the Scrum team. The PMM as a stakeholder is helping to figure out the go to market strategy, etc, and execute on it in their own agile team.
Again, I stress that each organization can do whatever it wants. I just don't enjoy it when articles like this are referenced to as evidence for why X person's role should have Y responsibility, etc. It's teamwork. Everyone takes responsibility.