When people ask for a commercial service hookup there is usually a charge to bring transformers and service lines to the building. This is a constant cost based on the load. The infrastructure to run the service lines out to a new commercial district are usually borne by the residential rate payers. It's how utility monopolies work in any of the states I've worked in.

So, you could think of it like this:

New customer: 100k-500k. Existing customers: 5% rate hike or 1M-100M/year in increased payments.

Per customer this may be minor but there are many customers.

The problem has been we have no system for proactive construction of new generation. Note: up until recently in the US demand has been mostly flat. We have been building significantly more power efficient systems so utilities did not know we would see a massive demand spike.

China somehow was able to harden against this and continued to improve infrastructure.