Actually, this isn’t “easy” and is huge news. You see, Lego is absolutely meticulous about their quality control. Their standards for manufacturing are stupidly high, as are their safety requirements. You know that distinctive “click” when you pop two Lego bricks apart? They engineered that. That sound is so distinctive that it can be used to tell genuine Lego bricks from counterfeits and it’s a sound that would be based on shape and material.
Furthermore, one of the hard requirements for a Lego brick is that it must be compatible with any other Lego brick. If I buy a set today and pull a set from the 1980s? Those bricks would fit together perfectly. This requires a huge amount of precision engineering and controls on manufacturing quality. (I can’t remember the source, but I’ve at least heard that once the brick molds wear to a certain point, they’re pulled from the line and either melted down or turned into construction material for Lego HQ. Point being, no one is getting their hands on a worn Lego mold)
Recycled and non-petroleum plastics are different from other plastic. The chemistry is different. The timing and process to use them is different. This has been a reason why more companies haven’t moved to them, because there’s a drop in quality for material (so they claim).
What Lego just did is completely obliterate that argument. The corporation with some of the strictest quality control requirements for plastic just kicked the basic foundation of the “bad quality” argument out from under it, because if they feel confident enough to guarantee the same experience as using a brick from over 40 years ago, if they are confident enough that they can meet their own metrics at a huge industrial scale….
Nobody else has any excuse.