In a past role when I was short staffed and hiring people, I was often lumped with interviewing people on top of my regular duties. It is a lot of extra work. It also took longer than I expected. I was often a bit late getting back to people for all sorts of reasons. Sometimes, candidates had to reschedule. Sometimes, more urgent work came up and I had to do things other than processing the applications. Suddenly, your last interview isn't Tuesday, but Friday instead.

I was never more than a few days late - the best candidates usually had more than one offer to consider and I'd lose them if I didn't get back to them. If they told you Wednesday, I'd give them until Monday before giving up.