I'd say that the development in Poland happened despite
I'd mostly say that too.
The bit some will disagree with is that Socialism (whether a distorted form imposed by the Soviet Union) or a more practical aspect of it was part (but only part) of the growth in education, infrastructure and especially housing in the 60s and 70s. Had it been left to capitalists and their 'markets' there'd have been more nice villas built for the better off (though not many, since not many could afford them) however the ordinary people would be living in far worse conditions, and be far less well educated..
It mirrors slightly the situation in the U.K. where the Labour voting areas in the north cleared slums, built polytechnics and hospitals whereas the south east (which lives of money generated in the industrial north) didn't spend the money that much and progressed more slowly until Thatcher's asset grab in the 80s.
These aren't perfect comparisons since the countries are very different and of course the economies of Europe would have developed differently. Another (imperfect) comparison is with the capitalistic South American countries with their huge gap of rich and poor or America with its desperate poverty in the rust belt (only mitigated by the post war boom at the expense of other countries) and conspicuous wealth elsewhere. We forget about the grinding poverty they had there in the 30s of which Steinbeck wrote.