It isn't an unsolvable problem though, there's only jitter because the implementation isn't very good

Implementing a more conservative anti wallhack cheat where player positions start streaming in slightly earlier still significantly cuts down on the efficacy of wallhacking, while entirely avoiding the jitter problem. Characters in CSGO move at a fixed speed, so you can calculate exactly how many ticks in advance you need to start sending that data in, before they will become visible to another client around a corner - and add a margin

There's also no excuse for sending player positions through a smoke for example - the server should be performing visibility culling

With the two combined you could cut the utility of wallhacks by 80%, in a way that would be completely unnoticeable. The real reason that this has never happened is that valve's investment into anticheat has always been pretty minimal compared to what's necessary for it to be effective (VAC has generally been the least effective anticheat). They're a small company which largely develops steam as a platform, not VAC or anticheat solutions for games