Sadly that's true, but there's still hordes of readers out there who actually want the cliches and formula tales.
I used to work at a Borders and would often speak to fantasy customers in the sci fi/fantasy section and would constantly be amazed at the different kinds of readers who'd come in wanting such diverse stories. Most of them wanted books to kill the time, I think for most of them on the bus or train (or in booming Perth, for up north on a minesite where they'd be stuck on a fly-in fly-out roster for two weeks).
If they'd been reading pulp like Forgotten Realms or Dragonlance and wanted more action I'd put them onto Brent Weeks (His Shadows Trilogy).
If they were getting tired of stock fantasy and wanted something a bit different or with more depth, I'd put them onto Patrick Rothfuss' Name of the Wind.
If they were instead looking for something to tie them over while waiting for George R R Martin, I'd send them onto Joe Abercrombie or Steven Erikson.
But in all that, the most numerous kind of reader was the one who just wanted to read an enetertaining story that usually held all the things we've mentioned above. That's why those tales keep coming out. Simply, they sell.
I think that's where a lot of fantasy readers start, but as you delve into the genre your taste becomes more refined as you sample so many different things.
Very insightful explanation!