I don't know why anyone is surprised the stub end Smithfield will close (most of it closed long ago and is already being redeveloped) - it has been on the cards for years, it's part of the area development plan that includes the new Museum of London site where the frozen meat warehouses were; yes, my butcher goes to Smithfield I think, but I suspect he'd rather go somewhere less shrouded in traffic jams.
It's grubby, stuck in what is no longer the right place (the traffic jams, no parking, no direct rail link) and generally past it's best by date. What does seem to be a problem is that they aren't opening a new single site location as they did when Covent Garden moved to Nine Elms 40 years ago, which is waht I expected
I walk through Smithfield sometimes, I love the old cast iron structure (which is listed), but the retail shops closed long ago, adn I really don't think it's ideal for a wholesale market not.
I can get quite nostalgic about going to the pub that opened at 5am to serve breakfast (and beer) to market workers; we would (rarely)go after all night events in our Laura Ashley frocks or bow ties, they weren't supposed to serve us of course unless we worked in the market, but if you were a fairly small, well-behaved, group you were fine as students. But that was 50 years ago ...(it suddenly occurs to me I must have walked there from Bloomsbury in heels, at sunrise

)