It would be very difficult to gauge how many CPL holders are awaiting their first opportunity. I mean, where do you start? With JAR, or EASA, there are countless numbers of commercial licenses issued through the various European authorities. I would say the vast majority of these are issued in combination with a ME IR. I would probably hazard a fairly even guess that most of these license holders will likely hold a MCC certificate. But who, if anyone, makes a record of CPL holders using their licenses to fly commercial aircraft for a living? (note, for a living!)
I know this does not relate specifically to your question, however you can see the difficulty faced with actually gauging how many CPL holders are still awaiting their first opportunity. There will always be those who are happy to share the fact that they haven't had a sniff of anything, however others will be more reluctant. Some will have previously failed an assessment or an interview, whilst others may have failed a TR, base training or line training. These people are out there, however you try and get them to be open about their situation. No one likes to talk about failures. Additionally, there will be those who will have let ratings lapse; whilst there will be others who have simply given up altogether. It would be interesting to know of the numbers, however I doubt we could ever find out?