> Digging a trench would probably pay for itself in a year or two.

I know some people running independent community fiber ISPs. Digging trenches can be a nightmare depending on the neighbourhood. You can have property ownership issues, other utilities being present, permit nightmares, different ground/soil types, etc. That ignores the fact that when somebody else digs they can hit your lines and repairing that is a pain.

Digging is better, though. But it’s not necessarily as easy as one may think.