> I am reading through a thread on how to scale a company, and one of the points is replace generalists with specialists. How can a generalist optimise for a long term career?

Pick up the management and leadership skills (including things like decisioning on incomplete inputs) and step up the ladder. Generalists are essential in the executive team to have the necessary context, make hard decisions, and own outcomes.

Alternatively, enjoy working in small teams (skunkworks-type product teams in large orgs, startups, or teams that are small by nature of what they do e.g in media and entertainment).