It is, but not as bad. The EU's birth rate is higher than Japan's, and the EU is much more immigrant-friendly - and if that makes you suck in air through your teeth, let me clarify - that's a relative estimation. SK and Japan are... infamously hostile towards immigration.
I don't go in for sports ball, but I do enjoy the memes
I mean, South Korea and Japan's birth rate is a serious problem.
The issue is less that they're going 'extinct', and more that the population pyramid is gonna look real fucky going forward, and that comes with... economic issues. And potentially cultural issues.
Me, at 80 degrees: "A little chilly in here."
That's the thing about population pyramids - they don't just move up evenly. They're adjusted by the ongoing mortality of each age group and the size of the next age group down. Poland and Japan are on the same trajectory, but Japan is, effectively, much further along. More ~30-40 years than ~10. The emphasis is less on the largest 'boom' generation, and much more on the general trend of the 'youngest' generations shrinking, growing, or being stable. In Poland, it's uneven - closer to shrinking than stable, but more stable than Japan, which is only shrinking.
Even relatively small differences can have an outsized effect in making the older generations an ever-larger proportion of the population despite their lifetime mortality going up with each age bracket. Compare the percentages here. "Boom" generation aside, Japan's retiree cohort is roughly 150% the youth cohort. That's not a good sign. For Poland to end up with those numbers in a decade, it would have to have effectively no mortality in the elder cohorts - extremely unlikely.
That being said, it is a problem for Poland going forward - as well as many other developed countries.