The complexity is added to achieve a complex goal. In the case of airlines, it's so that you can walk up to the ticket counter 45 minutes before a flight, slap down a wad of cash, and get on that flight... while still ensuring that every plane goes out completely full even when that rare event doesn't happen.
For restaurants, the complexity they're adding is fairness. They don't want to only cook for rich people, they want to cook for everyone. But their food is so good that if you sorted the net worth of every customer every night descending and invited customers in in that order, there would never be a person in the restaurant with less than 100 million dollars. So, to ensure that net worth isn't a factor on who gets admitted, they have to add operational complexity, basically distributing tickets by random lottery and ensuring that people can't sell those tickets.
The current system is basically a competitive auction with extra steps. The competitive auction ensures that only the people with the most money can eat at your restaurant. If you are a restaurant and you don't like that, then there is no choice but to move to a different system. If you're fine with it, keep doing what you're doing. Many restaurants already do that and they are full every single night.
For restaurants, the complexity they're adding is fairness. They don't want to only cook for rich people, they want to cook for everyone. But their food is so good that if you sorted the net worth of every customer every night descending and invited customers in in that order, there would never be a person in the restaurant with less than 100 million dollars. So, to ensure that net worth isn't a factor on who gets admitted, they have to add operational complexity, basically distributing tickets by random lottery and ensuring that people can't sell those tickets.
The current system is basically a competitive auction with extra steps. The competitive auction ensures that only the people with the most money can eat at your restaurant. If you are a restaurant and you don't like that, then there is no choice but to move to a different system. If you're fine with it, keep doing what you're doing. Many restaurants already do that and they are full every single night.