In 20 years? How on earth would they have pulled that off? Denmark, Sweden, West Germany, The Netherlands etc stand on hundreds of years of relative wealth and industrialization. Sure, the world wars didn't leave them untouched either, but it's much, much easier to rebuild an industry than to build it in the first place. And then they had the Marshall Plan, 50 years of peace, 30-40 of which were a giant seemingly never-ending economic power boost.
Comparing that to a country that only emerged from Soviet occupation in 1990, joined the EU in 2004, and didn't have a long history of self-determination more of less in its current form is like comparing a 12yo to a professional athlete and saying "well, if he wanted to, he could run a 5-minute mile, the other guy can do it as well, clearly he just doesn't want to".
You are judging Soviet-era Poland on the society which actually existed, while judging post-Soviet Poland on what they claim they are trying to achieve. That isn't fair. If you judged them both on what they said the goal is, you would have to compare the democratic paradise with the equally utopian and unrealistic communist paradise which was supposed to be just around the corner. Or you could judge them both on the actuality, in which case the present day looks like just a newer iteration of a grim, hopeless and broken society.