Businesses enter markets readily and leave them slowly. The asymmetry is not caused by poor analysis, since the arithmetic for exit is usually clearer than the forecast that justified entry.
Entry is judged on possibility, exit on evidence
An entry decision rests on a forecast, and forecasts are constructed by people who believe in the opportunity and can be defended in either direction.
An exit decision rests on results, which means someone has to state that a previous decision did not work.
The person making that statement is frequently the person who made or approved the original decision, which changes how readily the case gets made.
Sunk cost is treated as an asset
Money already spent should not influence whether to continue, since it cannot be recovered by either choice.
In practice it is cited constantly, because abandoning the activity makes the loss visible while continuing keeps it unrealised.
Continuing also preserves the possibility that the investment will eventually be justified, which is a comfortable position even where the evidence is poor.
Every activity acquires internal advocates
A product line supports jobs, and the people in them have accurate information about its prospects and a clear interest in its continuation.
Their arguments are usually genuine rather than cynical, since people close to something see the reasons it might yet succeed more clearly than the reasons it will not.
The result is that the internal case for continuing is always well argued and the case for stopping frequently has nobody to make it.
Shared costs disguise what the activity earns
A declining product often uses the same sales team, systems and overhead as the rest of the business, so its true contribution is a matter of allocation.
Different allocation methods produce different answers, and the method chosen tends to follow the conclusion the analyst expects.
The more useful question is what costs would actually disappear on exit, which is usually a smaller figure than the allocated cost and larger than the direct cost.
Exit costs are real and often understated
Leaving a market carries obligations to customers under existing contracts, commitments to suppliers, and consequences for staff who are affected.
Reputation matters too, since customers in other lines observe how the company treats those being discontinued.
Firms that plan withdrawal deliberately, with notice and transition arrangements, generally pay less in the long run than those that delay until the decision is forced on them.