I think it's worth pointing out that they haven't actually changed the law whatsoever.
They've simply made a clarification as how a specific situation should be judged in regards to when a player is deemed to be "interfering" after being in an offside position when the ball is played to him by a teammate. Which they do all the time, there are numerous videos and pics which denote match incidents and how they fit it the law, or how the law fits them.
It's the nature of the offside law as it stands now that it isn't a simple black and white decision, it is down to the refs interpretation that he makes based on how the law is written and the guidelines and clarifications issued by IFAB.
But even with that all they cannot cover every single incident that might occur during a game of football, hence incidents like Rodri and Mings that pretty much no one can agree on. But it happened and they've clarified that from now on it should be given offside. Thats kinda how lawmaking in football has worked over the years.