[specialist]

Spot on. David Roberts (Volts) also asked about that in one of his interviews.

IIRC, the expert answer was: substations generally need a retrofit (eg new transformer, breakers, smarts).

Even so, reconductoring is much faster and cheaper than building new lines.

Because retro doesn't require a new permit, often reuse existing footprint, and substations can be upgraded as needed (eg only for sections pushing more power).