So first of all, 18 inch counters are a little cramped, so this regulation means that nobody gets a counter big enough to have small appliances or ingredients containers and still has space to put a cutting board or roll dough in front of it.

I think it depends on how the code deals with corners. If 18 inches apart means that I can have the first outlet 18 inches from a corner, then I might be okay, or I might have to make 15-16 inch deep counters so that you can reach it even though it's right near the elbow.

If the 18 inches means I have to place outlets 9 inches from the corner, then you can't reach them. Or if you can convince them that Pythagoras was an okay guy and 12.75" from the corner is fine because 2 * 12.75^2 ~= 18^2, I'm still not quite able to reach those outlets unless I make a kitchen with crazy shallow counters.

The only other options involve chopping up the counter top into alcoves with the outlets set forward, including filling in the corner of the L. Otherwise you have to move the outlets away from the walls, which means not only are cords dangling all over your kitchen, but they're being exposed to fluids, either of which is so stupid that it should be against code but probably isn't.

I think the implication from OP is that effectively the only sane reaction is to build galley kitchens, (which might be better for people on canes or crutches, but would be difficult for people in chairs, and generall suck for everybody), or to build the oven or microwave into the corner to fill the space and/or give a reasonable spot to put an outlet.

But both of those essentially destroy the value of the corner, which is to house an arbitrarily large countertop appliance of your choosing, such as a juicer, dehydrator, or commercial grade stand mixer. And with 18 inch counter depth regulations you're sure as fuck gonna need it.