That's a rationalization. The utility will already be balancing their budget to accommodate seasonal consumption. It happens
every year, it's pretty trivial to plan for.
Plus, you're making the very large assumption that all of these fees are actually being used for infrastructure. I think you'll find in most cases that the amount spent on infrastructure is vastly lower than the amount of fees collected.
I pay a service fee for my internet connection, and so do the other several million people the utility services. So why do new customers have to pay thousands of dollars to have a new fiber run down their street? Why is infrastructure not upgraded to handle the actual load? Lines are so oversold that you typically get a tenth of your rated bandwidth, on fiber.
Always remember that the utility is a for-profit company. Their goal is not to maintain high standard infrastructure and service, it's to make money. So they add on little fees that sound reasonable and hope you never think about it.