Process isn’t everything, but they’re not just marketing. The process has a huge impact on the heat & power characteristics of the core, and also controls how much stuff you can stuff into a die.
The point he's making is that 10nm, 7nm, etc don't actually denote anything that lets you do an apples-to-apples comparison anymore. At this point, they're not measures the way they were in legacy process nodes.
They haven't been apple to apples in over 20 years. But being stuck on one feature size for more than 2-3 years is still a major roadblock to performance improvement.