A tree falling can be addressed by vegetation management and trimming. A power line sagging because of excess heat is operator error.
These are not remotely the same.
I hate this term, and look forward to using it all the time.
As you have identified A wider right of way costs more.
Usually for lines above some voltage, perhaps 200kV, the cost of an outage due to a tree strike outweighs the cost of additional vegetation management so they will clear the right of way wide enough that no tree can fall and hit the power line.
Around here for 130kV the right of way is still as narrow as it can be and we annually take down the riskiest trees as this is the best for our budget, which is not unlimited.
