A few people in Poland make tons of money
agreed mate! actually these areas (Katowice & Warsaw) could be areas where there are top CEO, directors and other big 'fish', the salary is being divided among the inhabitants around there.
what i mean here is that there are many people earning a lot and the distribution, when it comes to the workforce still stays strong. Just need to do some Maths and you will get the reality.
for example, in London, there are many big 'fishes' so when the mean income is calculated, they still come out on top. because of the gap compared to other counties.
Well, some people might change their mind and move to these places, however, be careful as you are not aware of the cost of living yet. I bet any Polish person can say that in these places, the cost of living would be signinficantly higher.