Regardless of local population of each state, the above incoming number of arrivals is reasonably similar (above 100 below 500).
But each arrival has the same chance of having Covid 19, the same chance of a mild or serious case and the same chance of requiring a ICU bed. Each arrival is unknown.
We do know the total number of ICU beds, medical resources, funding, and cost of delivery across the states and territories and that is disproportional.
Fed funding (millions) for WA is $2,521 while NSW and Vic get $7,212 & $5,876 respectively.
It is clear Vic has gone into overload on it's health system, so it is logical that WA with a much smaller budget will have a much smaller ability to deal with a Covid breakout. Far less than half that of Vic given the cost of delivery in WA.
Xeptu - We can not stop arrivals of our citizens, some are being "evicted" from countries they are currently in, they need some place to go.