It's true if you read it as "breaking backwards compatibility is easier". Intel x86 chips would have had things like out of order execution many years earlier

It's true if you read it as "breaking backwards compatibility is easier". Intel x86 chips would have had things like out of order execution many years earlier if they didn't need to be compatible with old software. Some people have said that a lot of the 737 Max problems are due to Boeing execs insisting on keeping the same airframe. I admit that isn't quite what the parent said, but realistically any architecture "from scratch" is going to reuse a lot of stuff from existing designs that works well.