Interesting interview with someone from the Trust that monitors lions like Cecil, on BBC Breakfast earlier. They do not get public funding and rely wholly on philanthropy. The events surrounding Cecil's death has seen a huge amount of money being donated. Furthermore, he pointed out that limited trophy hunting can be beneficial both in terms of income generation but also animal control. I suspect this has something to do with the hunters killing to old and frail more than the younger, more fertile ones.
Furthermore, contrary to common concerns at the the time, none of ther cubs have been killed. It is thought that there was a second male in the pride, who may even have been the father of several of the latest cubs, who has now taken over from Cecil.