Only if they need a visa to enter Poland. If they can visit for 90 days as a tourist, they can just apply for a residence permit in Poland - which is much easier.
Right, that is why I mentioned to him that it might be possible to apply for a residence permit in Poland. So just to be clear: You need to apply for a Polish residence permit, which you can do once you arrive in Poland.
$3-4K USD / month is really good money in Poland. Poles make around $1k / month. I'm sure your wife will eventually find a job for 2-3K PLN / month and you guys will live better than most Poles (well even w/o her working you will). Having a Polish wife will make it possible for you to live well in Poland. Most foreigners get ripped off and therefore need more $ to live on.
Yeah, being ripped off is even a problem for Polish people that live in other countries and come to Poland. Still, that happened quite frequently during communist times also. Cheating and greediness was even more of an issue back then. A lost and naive person would be spotted and considered a frajer, easy pray to scam. Poland is definitely no place for naive people.
A common scam was when Polish people came to Belarus and were told they had to pay more because a percentage would go to Poland. Of course they were never told this if they did not notice that they were being scammed.
Just don't expect to get a job in Poland unless you are well educated and speak Polish. If you have some specialist knowledge that is in demand then you might not even need to speak Polish. There are of course exceptions but in general Poland has no need for uneducated foreigners.