Roughly, when Demand Gen is no longer the core function of marketing. This also often is the time when you are ready to expand beyond a core small, effective, efficient marketing team.
When you have enough of a lead generation engine going, AND enough of a brand, that brand and corporate marketing strategy and positioning are more important than finding new leads and helping search out raw new opportunities.
Put differently, once you truly have an established brand in an established category, the game changes. It’s then less about letting folks know you exist than letting them know why now is the time to buy. And reminding them why to buy from a/the leader.
Often this is roughly around $20m ARR.
Until then, maybe focus first on a VP of Marketing whose #1 job is being VP of Demand Gen.
You can add the rest on top of that engine.