Would you risk a huge amount of capital in fighting with PKO BP? They have such deep pockets (and such a well known brand) that it would be commercial suicide for any new Polish entrant to take them on in the same way.
Anyway, Poland rather developed the credit union network as opposed to conventional banking. The problems are well known and they should have been regulated better from the very beginning, but they did well enough.
But really, what does it matter who owns the banks? PKO proved beyond all doubt with their last results that a Polish owned bank was still going to screw the customer over to maintain profit margins and that there's nothing patriotic about them.
and next to no Polish-owned retail chains?
That's a matter of logistics. Poland developed a lot of good retailers (Empik, Smyk, Alma, Piotr i Pawel) and left the big retailing to foreign companies. You're forgetting that a lot of companies found in shopping malls are actually Polish, as well.
Bear in mind that Poland actually got the best of both worlds - we've got the large hypermarkets, but we've also got a very strong domestic retailing industry and several chains of smaller supermarkets that do very well for themselves.
But you know - one thing to remember is that if you want strong Polish companies, you have to create a business environment that allows them to flourish. PiS are just about the tax the hell out of water use, which will heavily hurt food producers. Poland is quite clearly capable of being a European powerhouse when it comes to food - so why are PiS doing this?