115 years using labor and materials from 115 years ago. No guarantee it
will last that long next time. Are you sure it never was serviced during
that time? Likely, just forgotten.

What's that got to do with anything? Of course it's going to
need maintenance. All roofs require maintenance. The point is,
the current arrangement does not appear to be broken in any way,

Venting is SOP on almost every roof I have seen.
In the summer it equalizes
the attic temp so ice damming and other freeze thaw problems are reduced.
There is no evidence that ice damming or other freeze-thaw problems
exist with this roof. How far past zero do you want to reduce them?

In summer it lets excess heat and humidity escape helping to keep the space
benieth more comfortable and extending asphalt roof lifetime.
Assuming it's an asphalt roof, this may be an issue. Or, as far north
as OP is, excess heat may not be a design consideration.