While this is an interesting optimization, the gain is not enough.
I close this issue for now.

@Marco Sulla
Optimizing dict is a bit hard job. If you want to continue, I have an idea:
`dict(zip(keys, row))` is common use case. It is used by asdict() in datacalss, _asdict() in namedtuple, and csv DictReader.
Sniffing zip object and presizing dict may be interesting optimization.

But note that this idea has low chance of accepted too. We tries many ideas like this and reject them by ourselves even without creating a pull request.