The $$ savings may make installing the infrastructure in loading/storage bays worthwhile.
Most distribution centers, factories, etc where trucks load/unload at docks already have 3-phase power from the utility. They may need a transformer and service upgrade or for really large fleets they may even purchase 480 or KV power but when you compare it to the fuel savings its a total no-brainer. If you can save $50-80k per truck per year vs diesel that savings makes the EV trucks free. $1m for electrical upgrades? Sold. Will utilities need to perform distribution upgrades? Yes, but not all at once. They will do the upgrades as demand rises just like they do today.
As many others have noted in this thread it all comes down to your routes and logistics. For local and short-haul where the trucks return to a home base they are an excellent fit. Even if you need 50% more trucks because some of them are always on the charger as I noted the fuel savings make the trucks free so it doesn't matter at all.
It remains to be seen what the maintenance burden is. If it resembles passenger cars in any way I'd expect maintenance costs to be much lower since more components can be permanently sealed with lifetime sealed electric motors so no belts, hoses, bearings that wear out because someone couldn't be bothered to grease them, etc. Some consumables like brakes should also last much much longer.
Part of this is how the law catches up. In some states only a utility can legally sell electricity which means billing for charging is weird.
Setting aside the cost of diesel for a moment, trucking companies didn't build the entire gasoline infrastructure, either.