Actually, you've given your answer right there without realising. The Cabal had been fighting Oryx and running from him for a very long time. Oryx and the Hive have been fighting the Vex. What a lot of people don't realise is that upon taking down Oryx, we've freed up the Cabal to mount a full assault against us like nothing we've ever seen before. Do you recall the distress signal they sent back to the Empire? Killing Oryx was the message they needed to send their full forces. We also still don't full understand the goals of the Vex, either.

Good points. I see what you mean. It just seems if the cabal can make it to the tower then what stopped oryx for example? The Traveller's​ light? The cabal don't appear to be in league with the darkness like the hive and vex. You are a warmind right lol. You know a lot.

Oryx's darkness did reach the last city. In the mission on twilight gap for the Ntte, you are burdened by the darkness set by Oryx.

We did; the Guardians. We found out he was coming due to the sacrifice of the Reef Awoken by their queen. That's the only real reason Oryx didn't make it to us as he intended. We then went in and stopped him before he could launch a full-scale invasion. The queen's sacrifice is the reason we had a chance. [i]War is a science with rules to be applied.[/i]