Not sure where you live but that's not the case everywhere.
It's not that they don't have access it's that it's an inconvenience and not a high priority to get it signed asap when the process had already taken 6/8/10/12 weeks.
All of which are done online with little to no effort and not even close to comparable to finding a notary.
The only time in my life I have needed to find my own notary was selling
DVC. It's also something in our area less and less places are even doing it.
In addition you are dealing with notaries that you call or email and think a response will come and 3 days pass before you realize they never contacted you back.