The first responsibility of the pack committee is to recruit the best person available for Cubmaster and provide this person with one or more assistants. In the case of an existing pack where there is a functioning Cubmaster, the committee will simply want to create and maintain a close working relationship with the Cubmaster and assistants.
Most leaders are involved in the pack primarily because they have sons in it. It is almost inevitable that when there sons graduate from the pack, the leaders will, too. This will leave gaps in the pack leadership, and recruiting will be necessary.
Scouts deserve the best program possible and they will get it from qualified and enthusiastic leaders. Leaders should be selected because of their qualifications and not recruited because no one else would do the job.
When recruiting leaders, don't limit your search to parents of boys in the pack. Many times a former leader or a member of the National Eagle Scout Association is willing to help. Grandparents or other relatives make good leaders, too. There are many Cub Scout leaders who don't even have sons. There are senior citizens and retired persons who would be glad to help. Consider all possibilities.
Once new leaders have been recruited, do not leave them high and dry. Actively help get them started. The Fast Start Videos (available from the district training team or the Scout Service Center) are excellent materials. So You're a New Cubmaster, A New Webelos Den Leader, and A Pack Committee Member are pamphlets available to help in recruiting. And remember the chartered organization has a responsibility to help provide leadership for the pack.
If you have difficulty in recruiting adequate adult leaders, seek help from your chartered organization, Scouting coordinator, or Unit Commissioner.