A D&D setting with no problematic areas? Sounds like a fantasy world to me.
Seriously though, WOTC has no financial incentive to make a new setting. It's attracting quite a few players new to the hobby with generic Realms-type material. I'm very sure it's taking a lesson from the bankruptcy of TSR, which previously owned D&D, in that TSR actually harmed itself by putting out too many settings (over a dozen for AD&D alone). If my table plays Dark Sun all the time, I'm probably not buying incompatible material like Lankhmar or Council of Worms.
So far, the 5E model has been to give us an adventure or sample of another setting. Wildemount has been the true exception, but it came with built in hype thanks to Critical Role. For WOTC, it was perfect. Someone else had already built up the hype and established a demand for the product, and it works with all material we already had.
If we look back at Dark Sun, it was surrounded in AD&D with a lot of hype: novels, video games, and marketing efforts. Same thing in 4E. Big exposure at conventions, novels, a free adventure, promotions, and again hype before the product hit the shelves. It paid off. Both were best-selling lines at the time.
So I'm curious if WOTC will someday go big and bold and hype up a new setting. It's a big risk for them, but they do have a pre-existing successful model. However, until the winds of the market change and players get tired of the "same old thing," I don't expect to see much more than another adventure in the Realms.