You mean 90% .

80%  you are still missing 20% of the DCI color palette .  And then moving on to some movies which are mastered at Rec.2020 , it is going to miss even more .
And WCG is only the first step , there is also color volume which is typically the strong point of Quantum Dots and very bright FALD TVs .
Every modern TV can call themselves a WCG TV thesedays because the modern basic 4K TV can cover 70-80% of DCI  chart which is still more than the traditional SDR TV which is only meant to fill up the old rec.709 .
I believed all the big TV brands (namely the big 4) have a certain standards to adhere to . So if they are saying their TV supported WCG , it means that tv can practically reach over 90% of DCI , or at the very least  close to the 90% set by UHD alliance .
For eg , LG has specifically mentioned their UM7600 covers a wider color gamut , except the 50 " model which will probably fall short of the 90% .
Dolby Vision is a type of HDR format , like HDR10+ , HDR10 , Technicolor and so on.

WCG being one of the hardware requirement to display vibrant , impactful and realistic HDR effects.

So to sum it up , TV of any spec with DV chip installed can theoretically play DV content  , but whether if the Dolby Vision will look as vibrant and as good it should , that will have to depend on the TV spec with WCG being one of the requirement .