That doesn't matter. Only growth of manpower matters. The fundamental problem stays the same regardless of how many people you have.

If you add code and revise 50% of it every month, the code base is bound to grow and the share of time spent on maintaining the old code grows as well until development of new code grinds to a halt.

Unless of course there is massive growth in hiring. But that isn't sustainable.

[Edit] Well, I forgot one possibility: Deleting code.