You would seem to be saying that grid infrastructure needs continual refreshing and improvement to continue carrying the same amount of power? That strikes me as a tall claim, given what I already know about electricity (electronic design and house wiring). I am open to entertaining it, but you've got to provide a reference or at least just describe the mechanism.

This is talking about the capital assets themselves, which are of course separate from regular maintenance like tree trimming.

About the only thing I can think of is something like a bulk of the grid infrastructure was built out 30/40/50/whatever years ago, and is now all reaching its expected lifetime all at once, and perhaps some types of equipment are strictly retired at the end of their lifespan lest they fail catastrophically.