The attendances at the WACA are irrelevent from now, sure 15 000 turn up for a test match but some people dont want to go and sit in a shit hole all day. Moving tests and other big games to the NPS will attract more people due to the better facilities it will have. If you think there will be a huge amount of extra seats think of the Perth Arena and the Wildcats. They played at Challenge Stadium which is rubbish and only got 5000 but now they play at a decent stadium and they get 12+ even though everyone thought it would be half full . I reckon Perth could get 30 000 to tests at the NPS but thats just my opinion
That's the biggest fallacy I continually keep hearing, move Tests to a better facilitated ground and the people will come. The results are that is simply not the case. Compare Perth to Brisbane, which is a similarly populated city, but has a world class stadium in the Gabba. Despite that non-Ashes tests regularly draw less than 20k through the gates. Day 1 of the NZ test drew 16k and yesterday drew 14k. Last year day 1 verses India drew 15k and it dropped to under 10k from Day 2. South Africa in 2013 at least drew 25k day 1 but that dropped sharply to 11k day 3.
The reality is there simply arent tens of thousands of people sitting at home who are thinking to themselves 'I'd love to go to the Test that's on today but I wont because the WACA is crap.' 15k in the fishbowl that will be Perth Stadium will be terrible for atmosphere. Test matches have reached their peak in terms of attendance and the only thing that could improve that is day-night tests, which Perth will never be a part of due to its timezone. I've said it before, only an Ashes test would warrant the move to Perth Stadium, and even then I imagine that day 3 onwards will draw crowds that would fit into the WACA.