Is it is necessary to do type rating after getting CPL to serve in an airline? Can it be done after some time?

Type Rating is not a compulsory requirement after completing CPL. But the logic of doing TR is to reduce the number of competition for any vacancy. For example : There may be 2000 CPL holders in the market but the number of type rated Candidates be may around 1000. So for a vacancy of 200 you will f