Aborted for a reason.
When they got the architects who designed Beijing's Bird Nest involved and announced that stadium design, they were surely thinking they'd be getting a fair wedge from their owner to pay for it. And I'm sure it's not coincidence the announcement it'd been put on hold came the same week Roman's visa problems emerged.
That thing would've cost a bomb, easily into the realms of some of the crazy NFL stadiums in terms of costs. There was talk of them buying a brick factory to produce the 6 million bricks needed, every element looks a different size and shape. It's effectively the cost of a normal 60k stadium, plus the cost of a giant columned steel/brick frame encasing it....absolutely nuts...
The upshot being, that kind of design isn't possible without a very, very generous owner or NFL-level revenue. Chelsea are rich, but left to their own devices, not that rich. In future I reckon they could pull off a more conventional steel/glass stadium build with some unique features (i.e. like we've done), but the brick egg-slice was always Roman's vanity project.
So yeah, if you're looking at half a billion for your stadium, probably best not to expect something that would cost at least double that.