The economic potential of Poland and Russia cannot be compared. It's much easier to become rich in Russia than in Poland.
1. Potential is one thing, the reality is another.
2. There's much bigger gap between the rich and the poor in Russia than in Poland.
3. And it's not just about money. It's also about the quality and standard of living, the infrastructure, the maintanance of the neighbourhoods where people are living in, level of corruption, the way people behave and are treating you, etc. In all of those cases Poland seems to be a better destination than Russia. Those are not my fantasies - I'm writing this based on what Russians who moved to Poland are saying.
I get called an orc ten times a day
Because you deserve it.
I suspect Ukrainians view Poland as a gateway to Europe, of sorts. The first stop on the road, if you will.
I also thought that, and probably it is the case to some extent, but many stayed and even many refugees are staying.
For example, I'm watching a YouTube channel of a Russian-speaking Ukrainian from Mariupol who moved to Poland two years ago, for example. She's making her videos in Russian, so I'm guessing it's mainly for the Russian-speaking viewers. She's completely smitten with Poland.
That's maybe not so strange, but there's another YouTube channel that I'm watching which is more surprising - a Ukrainian guy who moved to the US with his family when he was a kid and grew up in New York (he even talks like a New Yorker lol), lived for some time in California and other places in the world moved back to Ukraine, to Kyiv. But when Russia invaded he fled to Poland with his girlfriend. And he fell in love with Warsaw. He often makes comparisons on his channel - Poland vs the US vs Ukraine, so that's quite interesting.
Here's one of his videos (in English) in which he walks around Warsaw and talks about the differences between Poland and Eastern Europe: