I want to let this go, but I just can't.

No. Not true.

Everything, everything, within a structured storage engine comes with trade-offs and costs. Nothing is free. TANSTAAFL always applies. But a properly normalized structure with appropriate indexes and enforced referential constraints generally outperformers a flat, denormalized structure. This is because the relational engine is optimized around supporting the relational storage and retrieval of data. Can we identify situations where this is not true? Absolutely. But by and large the normalized structure is superior for the types of applications and needs that structured, relational storage is built for.

We can go down the road of talking about id/value pairs of unstructured storage for data collection. But, they don't support querying the way relational storage does. So, different requirements, different structures, different performance paradigms. So, if we're talking about different applications and different needs, then, yes, relational storage falls off a cliff and normalization hurts performance. But then, we shouldn't be using a referential engine for the storage anyway.

Sorry, so sorry, just saw this statement one too many times this month.