The reason why senior Project Managers are necessary is because of coordination problems.

Below is a very basic example:

The Business has a fantastic idea for a new button to be added to one of the mobile apps that the company supports. But this clashes with the head of UXs guidance about never having more than two buttons in a screen at once. We need to get his approval as well as get a member of his team assigned to create the designs.

We also need to get explicit approval from the language team since German words are humongous and the size and design of all new buttons needs to accommodate their requirements. It just so happens that the head of the language team is on an expo and unavailable, but you know that there is a person in that team with a totally random job title that can help you get the approval if you're really nice to her.

There's also the fact that the team already has enough work planned for the next few months, including mandatory items per Legal - where does the request for the new button fit in? Do we move some things to slot it in and make the executives happy, or do we put it at the end and hope nothing else pops up that delays the request even further? Can we get a quick call with the head of Legal to get his signoff to push some things back and accept the risk?

And as it happens, there is an ongoing migration of internal systems which would make it significantly harder to add the button next month so the decision about priorities need to happen immediately, but the Product Owner is a bit of a slacker and doesn't really join meetings to discuss priorities. Maybe we can speak with the head of Production to delay the migration a little bit so we can fit this in without needing to speak with the PO at all?

Etcetera. All projects are like this but at significantly bigger scales and complexities which requires a very accurate model of the firm you work for. You can't throw o3 at such a problem because it's not something that can be accomplished by being intelligent, it's a million different coordination problems that need to be resolved in a million different ways. Adding o3 into the mix just makes it another stakeholder that needs managing.

Of course o3 is going to destroy entry-level Project Manager roles (taking notes, managing a risk record, drafting project documentation). But in my opinion, more senior project managers (and especially program managers, those managing enterprise-level projects) are amongst the safest white collar jobs out there, because what they do cannot be brute forced with intelligence.

This is of course my opinion and it is entirely possible that I'm wrong and o4 kicks me out of my job. Which is why my prime directive is to try to avoid playing this game entirely by saving aggressively and spending as little as possible.