Yes but the problem is they should have known that when they started. They had to have planned ahead. Why is it that 4 years in they started thinking about resource management?
In game development very frequently things on paper sound great, but when starting to implement them you see that certain things don't work or perform in the game as it was estimated, and should be improved or changed by other ones that as seen in other games or in internal prototyping work better.
Or there are things that did work when you started to develop the game but years later the market changes and players no longer like one thing that gets outdated and prefer something else new that appeared on similar new games. So in mid development important changes are made to adapt the game to the modern market tastes and trends.
Sometimes these changes are relatively small and don't require extra development time or resources. Sometimes they require a lot of extra time or even reboot important parts of the project, causing delays or to require more manpower.
In game production, quite often at the start of the project they add 50% on top of the initially estimated development time to the time they estimated that will take to make the project to consider all these unexpected changes.
One thing it may have happened looking at what ND said, the timing of the delay, the cancellation and the SIE Center of Live Service Excellence creation is that maybe they had planned the project properly, but in a review of the project by the center or in playtests once the game was developed enough to make them, they highlighted that this project didn't have a big enough post launch content schedule or budget to be successful in the long term.
As a result ND would have delayed the game to review this post launch part of the project, and after analizing and planning it properly found out that it would take them more post launch resources than ND wanted, but even considering future headcount growth they wouldn't have enough headcount to also work in the SP projects they wanted. Having to choose between the MP game and SP games, ND prefered to kill the MP game and focus on SP games instead.
People with a lot of talent and experience are still humans, so sometimes they make mistakes too. They make have a lot of knowledge in some areas, but not in other ones.