just like Romania and Bulgaria
Romania and Bulgaria are poorer. Their HDI is not very high (just 'high'), and a Pole, on average, earns twice as much as a Romanian/Bulgarian.
But on EU scale they are poor.
What is poor? Ever been to Poland, Milky? When you drive a BMW in the alleyway of your own house, you're not really poor, are you?
Yes, on average (because it's all about stats), Poles make less money, but life is not as expensive as in some other EU countries, so on the whole, the gap is not that huge.