[argonaut]

Both you and renesd are correct.

Renesd is correct that "big data" is overblown. There are diminishing marginal returns - you need orders of magnitude more data for the same incremental gain (and this blows up well beyond however millions of cars Tesla can hope to run).

You're correct that data augmentation is only a marginal technique to squeeze out more performance, and not generally possible in many domains.