Ehh... not entirely true. It's the "gold standard" because of cost and (lack of) need. It's an elegant solution for non-functional cycling.

Band-drive systems with internal hubs are superior for commuters who need reliability over anything else.

Tubeless tires are now the standard for riding on irregular terrain.

Disc-brakes are not the standard for hilly areas or people who ride at high speeds.

Meanwhile, single chain-drive fixed/free gear bikes are still perfectly serviceable for most use cases (even if you need to select from a few different cog sizes to fit your area).

The reason why "chain drive and pneumatic tires are the gold standard" is that most people don't ride bikes. If people did, you'd see much, much more variation in technology on the street, as they would be used for functional purposes, rather than recreational purposes.