That's what they charge here Archie (and more) when those teams come to the USA to play in pre-season 'tournaments' so I'm guessing they'd want similar revenue streams if they were to not do that but play at Rotherham...etc. As you say, if you wouldn't even pay 50p where's the incentive to play against 'big' clubs when the object of the exercise has nothing to do with the level of competition/results and more to do with the other aspects I mentioned.
PS Did you see my question about Meadow Avenue on the Icky to Derby thread? https://boards.footymad.net/showthread.php?t=38291274