We are in the middle of multiple world conflicts, through regional proxies. People are experiencing the consequences of those conflicts, even dying. They are afraid of the continuing effects. Others are scared of possible future conflicts. Your question was probably meant for a specific group of people. When you say "we", who is that? If you mean something that affects the U.K., like the setting of Threads, then it's just a matter of distance and scale. Most people in the U.K. aren't exposed to a direct threat of kinetic conflict, but that doesn't mean the rest of the world is not in physical danger of some kind.
To answer your question directly though, I think we have multiple generations that have grown up believing that anything they see on the internet is not actually real or is happening to somebody else. That includes war. The idea of a global conflict is just a Netflix plot or something, not anything that could actually happen. Few people have met a combat veteran or war refugee, but lots of people have played Call of Duty. That's their reference point. It's just not real.
Consider this, even with all the condemnation of Russia over the invasion of Ukraine, the sanctions, the shipment of arms. We are still using Soyuz spacecraft launched from Russia to go to the space station. We still share resources for all of that, including lots of money. That means there is a limit to the outrage, when it comes to economic and structural needs.