Well if a high number of nodes would be pruned it would be very difficult to sync a new node (pruned or not). If you consider that you only establish 8 connections and while syncing the nodes dont seem to create more connections, you will need at least 1 not pruned node out of 8 to sync.
Why is that? If you are trying to run a pruned node yourself, wouldn't it be the same as the normal syncing process that we have today? Aren't you just trying to download the latest data which other pruned nodes have?