Yes, but the restaurant has set prices they think are appropriate for their food. They want to be open to any customer willing to pay $x per person to eat, more

Yes, but the restaurant has set prices they think are appropriate for their food. They want to be open to any customer willing to pay $x per person to eat, more or less. Scalpers make it so that people who can only barely pay $x per person are supplanted by people willing to pay much more. These people have higher ability to pay, but that doesn't mean they will receive as much utility as the people who are being priced out. The restaurant cares about increasing people's utility, not about only serving a the wealthiest fraction of people who can afford their food (those with the highest ability to pay).