In practice the Pareto frontier isn’t necessarily static because background variables may be changing in time. As long as the process of moving towards the frontier is much faster than the speed at which the frontier changes though we’d continue to expect again the motion of going towards the frontier and then skating along it.

For a model of how conflicts of optimization (especially between agents pursuing distinct criteria) may evolve when the resource pie grows (i.e. when the Pareto frontier moves away from the origin), see Paretotopian Goal Alignment (Eric Drexler, 2019).

There can be a common interest for all parties to expand the Pareto frontier, since it expands the opportunities of everyone scoring better at the same time on their respective criteria.

Added my bio. It needs more work. Thanks as well for the nudge!