Have a look at where all the newer world championship races are, all new circuits in the middle east that get no spectators but pay the series owners well. The night time motogp race is the perfect example but I guess at least the riders are not battling heat exhaustion, TV rights are where its at for these guys
V8supercar,Dorna etc are all the same, as long as the circuit owners are prepared to pay them they'll send them the entertainment & nail anyone financially who refuses to go