Indeed huge sums of money may be put at risk in terms of lost sales by not defending key products. The cost of protecting a brand from infringement can be considerable. At one end of the spectrum the international music, software and motion picture industries spend millions of dollars on anti piracy activities. This amount includes the salaries of two full time lawyers and a full time clerk who scans advertisements around the country to make sure that companies are not using its trademark improperly. Some companies spend very little either due to ignorance of the long term impact of counterfeiting on their business or because they are small have limited resources and simply cannot afford the time or expense of running an anti counterfeiting campaign.
Litigation can be very expensive in some jurisdictions.
However many cases are settled without recourse to the courts and other less expensive anti counterfeiting strategies such as using the criminal law are available.