Those numbers are outdated and predate the invasion. Russia has gained several million new Russians by conquering Ukrainian territory and through refugees, Ukraine has lost millions through emigration.On that:
This is one of the unexpected factors in this war. Initially morale was a big worry but after the invasion began more people returned to fight than fled the country. There was a consistent net inflow of men despite a very clear flight taking place as well. While there was a period of chaos and panic - especially during the first days when the outcome of Russian operation was unclear - after the first few weeks Ukrainian military began turning away people who haven't served or had no military experience. They can afford to do it even with the casualties of the conflict which now are around 100k because well over a million people reported for military duty.
This is male population pyramid for Russia and Ukraine:
View attachment 107418
I agree that even if we take the highest estimates casualties numbers from both sides it's unlikely to change much in demographic terms. Higher numbers were lost in both world wars and all nations recovered.
There are a couple reasons I think the Ukraine is doomed if this war continues as long as I expect it to.
1. Refugee crisis. It's mainly younger Ukrainians leaving for western Europe and Russia. While some Russians may be leaving Russia, they at least will have a country to return to that hasn't been devastated by war. I think we'll see as many Ukrainians go back to Ukraine as we saw Syrians go back to Syria.
2. Fertility rate. The Ukraine's fertility rate was already one of the lowest in the world. Using WW1 as a comparison, crude birth rates of France and Germany dropped by half in the peak years of the war.
France (I've highlighted the CBR ‰):
1913 | 41,620,000 | 795,851 | 736,937 | 58,914 | 19.1 | 17.7 | 1.4 | 2.4680 |
1914 | 41,630,000 | 757,931 | 774,931 | -17,000 | 18.2 | 18.6 | -0.4 | 2.3354 |
1915 | 40,620,000 | 482,968 | 747,968 | -265,000 | 11.9 | 18.4 | -6.5 | 1.5194 |
1916 | 40,020,000 | 384,676 | 697,676 | -313,000 | 9.6 | 17.4 | -7.8 | 1.2304 |
1917 | 39,420,000 | 412,744 | 712,744 | -300,000 | 10.5 | 18.1 | -15.2 | 1.3419 |
1918 | 38,670,000 | 472,816 | 867,816 | -395,000 | 12.2 | 22.4 | -10.2 | 1.5593 |
1919 | 38,600,000 | 506,960 | 739,901 | -232,941 | 13.1 | 19.2 | -6.0 | 1.5907 |
1920 | 38,900,000 | 838,137 | 675,676 | 162,461 | 21.5 | 17.4 | 4.2 | 2.6946 |
I don't expect Russia's birth rate to change much as mobilisation has been limited to reservists.
3. Unlike France and Germany 100 years ago the Ukraine's population pyramid is fundamentally flawed, it was close to giving way anyway (as is Russia's). Since this war has a relatively low civilian casualty rate, it will be the 18-49 group that will be most affected.