While your location can absolutely still be tracked (via WiFi, Cell Towers, etc), disabling GPS significantly reduces the accuracy of this tracking, and disabling location history makes it even more difficult to freely track you.
While it's certainly possible Google maintains location history even after you opt out, doing so would likely be illegal, would possibly invalidate any data obtained from a warrant, and would unquestionably be a PR fiasco for Google when it got out.
As far as I'm aware, there's no evidence that GPS continues to function after turning off the software kill switch.
I have many apps I can use offline, plus if I need to use my phone it doesn't take long to turn it off airplane mode and have everything reconnect. It's amazing how fast all the notifications come in once you turn off Airplane mode. I don't do that daily, but when I am conscious about battery usage I do. Maybe I just might try doing it more often. I also do it when charging my phone.
Don't act all snarky when someone says the only way not to be tracked is to not carry a phone. It's pretty close to being true, and you don't know if hitting the software switch to turn off your GPS really turns it off or if it goes into a low power mode where it only updates your position every five minutes- this is not unheard of to keep the time to fix low for when a person turns location services back on.
As mentioned in the article, Google was previously caught tracking people even when they had location, data, and Wi-Fi turned off. We just have to take their word now that they don't do it anymore, and the word of a big profit driven corporation that has been implicated in PRISM and previously tracked people isn't worth too much.
Furthermore, even if Google doesn't track you the cell phone companies still know which tower your cell phone was connected to, so they know your location within three miles at all times. It's not as precise as GPS info, but the police could still ask the cell phone companies to give them a list of phone accounts that were visible to a specific set of cell phone towers at a particular set of times.
It does something that's completely useless since you're already being tracked by other means. By the mechanisms of physics, you can't have untrackable wireless communications. It's not how radiation works.