I couldn't imagine that there would be a 'non compete' issue between the V30 and the new Pixel, but I could see there being a supply issue of p-oled panels for both devices.
Another thing could be as simple as an issue that came to light during manufacturing (ie. some reviewers saying that the panel has 'bands' that appear in low light, etc).
Or another option was that the V30 was not ready to scale up, and LG wanted to get the V30 known before buyers spent their cash on the Note 8, and maybe the Pixel even.
The simplest explanations are usually the best ones, and I have a feeling that LG is just overloaded with getting display panels ready, and just announced the device to hopefully keep people from upgrading to another newly released device.