Perhaps it is connected in some way with recollections of Poland's decline from great Eastern European power status? Transference of unrealizable Imperial dreams onto the new great power?
[WS:] I think that this whole Great Eastern European Power business is mere wishful thinking of those living in a doghouse. It is untethered by reality, and I would not put too much value into it. Besides, most nations also have hefty doses of ethnocentrism, which makes them look inwards rather than outwards. Transference? Too Freudian to my taste.
To reiterate my argument, I think this outward look in Poland is rooted in the fact that for centuries the economic elites in that country relied mainly on cultural and material imports to express their social status. That set the tenor for the rest of the society, especially those aspiring to a higher status, such as the intelligentsia and petit bourgeoisie.
It is somewhat similar to hunting in the UK or the US. In the distant past, it used to be an exclusive privilege and a status expression of the lords, but in time it set the tone for other social groups and started "trickling" down - first to the noveau riche, then to upper middle class upshots and wannabies, and today it is mainly the domain of the riffraff, while today's lords pursue environmentalism.
Wojtek