I didn't see Insiders so I can't comment on the energy graphic but WA retail prices are not very different from East Coast prices. They certainly aren't one third of the SA prices.
https://www.energyplans.com.au/electricity-prices
It may have been the real time energy prices. However, these can vary wildly across the day depending on the renewable energy production and energy demand.
Insiders is on at 9am eastern which is 8.30am in SA but 6.30am in WA. Live energy prices are going to be much lower in WA at these times because demand is very low. In contrast, I'm writing this at 6.30pm WA time and the live price in WA is $120/MWh but only $20/MWh in SA.
You can see live prices here: https://www.gridiq.com.au/prices
