IN a business sense, the Egyptian underground steel wall is a actual physical barrier to entry into the smuggling market, meaning only Hamas and Gaza oligarchy approved tunneling operations will be able to continue operations, creating a near monopoly on black market goods, greatly enriching the Hamas leadership and further increasing the misery of the Gaza residents.
And yes, these tunnels can't exist, to the scale that they do today at least, if Egypt really didn't want them.
Without knowing details, my first reaction was also that someone feels they aren’t getting their share of the rake.