Pay for the meal. You’re out 20 bucks; my company is enlightening and if we work out, I will buy you something nice down the road that will totally make up for it.
I have more than enough money to buy my own meals and it is almost 100% socially acceptable to eat alone in restaurants. So, if you’re not going to pay and the conversation is mediocre and I can make the same meal at home for a dollar, why am I with you again?