Thing is, 8th isn't intended to run indoors. Its always gonna be an outdoor thing and dirt is the surface for it to be on, wether its nitro or electric.
They could be raced indoors, but it would have to be a purpose built arena which no one can really afford to build.
So they will always be outdoors.
....unless I win the euromillions one day!
Theres still lots of racing goes on outdoors during the winter so its not all bad news.