So they don't actually know what direction to take aircraft in and decided on stealth. Seems reasonable, all else being equal, the party that is detected last has a higher chance of winning. What happens when a new detection method is developed that makes these planes not stealthy? Don't you then just have 4-5th gen craft that cost 2-10x as much? Guess it takes a real war to discover the actual winner of modern warfa…
You can be assured that Russia and China are working hard on technology to detect stealth planes (e.g. multistatic radar systems). But again, it's not a binary thing. Even with a multistatic radar setup, a stealth aircraft will have lower detection range than a non-stealthy one. And considering both China and Russia are developing stealthy aircraft like Su-57 and J-20, it seems they themselves are not thinking that they have the magic technology that would make stealth obsolete.