That would probably be competition. A monopolist corporation has no incentive to improve its capital if it gets its profit anyway (c.f. the dismal state of DSL and cable). But if it's not a monopolist, it might be forced to anyway.
It's the same thing at a worker cooperative, or for that matter at a heavily unionized workplace: the workers have no incentive to automate themselves out of a job, but may collectively understand that if they don't, the business will go under and they'll all be left without jobs.