The window is smaller than it feels
A lead who filled in a survey this morning is a different person by Thursday. The intent that made them respond fades, competitors reach them, and the context that made your offer relevant is gone. Speed is not a nice-to-have here; it is most of the outcome.
Where the hours actually go
Almost none of the delay is deliberate. Responses land in three places at once, nobody owns the list, and the person who could act does not know there is anything to act on. The time is lost to ambiguity, not to workload.
What to change first
Give every response an owner and a status before you try to make anyone faster. Once it is obvious who is next, the speed follows on its own.