I would argue that the BASIC variants in 8 bit home computers were already GUI BASIC, given their capabilities and underlying hardware.

That wasn't the case with GW-BASIC, due to how MS-DOS came to be.

However the idea of an EFI BASIC does sound rather nice, assuming the whole plethora of graphics programming as well.

Other take the easy way out with RISC OS for the Raspberry PI, which has BASIC as main programming language alongside Assembly.