So called 'farmers markets', is a just a marketing trick. These often start off with some farmers / producers taking part, but then gradually evolve into yet another collection of street food vendors (take the one on Tuesdays on the Guys / Kings campus). There's more of a market for the ready made than for produce to take home and cook. Just look at the way Borough Market has evolved into a venue for '50 ways to scoff slop on the hoof', and the explosion in the volume of take away meals consumed, serviced by the plague of delivery riders.
Looking at the cast list of this latest lfm run site, there are only a small proportion of 'farms' involved, and most of those also offer 'cooked local foods', from which they'll make a far better margin at £6-7 or more a serving than their raw produce.
There's no 'marketing trick'.
Our emphasis over the last 20 years has been to run farmers markets. Some of our midweek markets evolved into more hot food/lunch markets because customers weren't interested in buying raw produce. Our Thursday market at Bloomsbury still has plenty of fresh fruit, vegetables, bread, juice, eggs, butter, cream, milk and more.
London Bridge started off the same way but has evolved into a lunch market. If you notice the signs they now say lunch market. We still have the same strict rules about ingredients and provenance.
At London Bridge Riverside we were asked to provide some raw produce which we've done.