To get the sportsman on that level one must invest in kids.
Very much so, however it can't be limited just to kids; it has to start there, and start seriously there, but the facilities, financial support and the trainers have to continue. At least that's what worked for the UK. Since Poland already has large sporting infrastructure, mostly due large-scale investment pre-1989, it has an excellent chance (and the structure still in place) to build on that. It would work.
No illegal scum invading their little islands a
Yet some who match that description tried invading them during the Bay of Pigs...
So easy peasy...