The problems that are left do not announce themselves. They show up as a number that stopped moving, not as a thing going wrong.
At Stage 01 and Stage 02 the gaps are loud. A missed call is obvious. An empty booking system is obvious. By Stage 03 all of that has been dealt with, so what remains is subtle: a room that runs at 40% on Mondays, a provider carrying too much of the revenue, a service priced where it was three years ago, a seasonal dip everyone treats as weather.
None of those cost you a client. They cost you margin, and margin does not complain. The business feels fine because it is fine. It is simply producing less than the assets inside it are capable of producing, and no line on your profit and loss is labelled capacity you paid for and did not sell.
This is also the stage where the temptation to expand is strongest and most dangerous. Opening a second site on top of an operation running at 66% utilization does not fix the plateau, it duplicates it, and now the same inefficiency runs in two buildings with two sets of overheads.
The work here is measurement first. You cannot optimize what nobody counts, and at this stage the difference between a good quarter and a flat one is almost always a number that existed the whole time and nobody was reading.