Hey there, I worked in the market for 5 years at a produce stand and still have contact with many vendors through my current job.
The big money customers are regulars who come down to the market weekly or bi-weekly to get a service level that is not provided at a regular grocery store. Those customers drop hundreds of dollars at multiple vendors and absolutely do drive through to get loaded up after shopping. Many of those customers are retirees that absolutely could not carry their purchases down to the parking garage.
The market is a very unique place and if it caters only to the tourists it will kill what makes it a tourist destination in the first place. It would become even more hollowed out as it drives away locals.