"There is a clear path to scaling up the network to handle several thousand transactions per second (“Visa scale”). Getting there won’t be trivial, because writing solid, secure code takes time and because getting consensus is hard. Fortunately technological progress marches on, and Nielsen’s Law of Internet Bandwidth and Moore’s Law make scaling up easier as time passes." - Gavin Andresen

Source: https://bitcoinfoundation.org/2014/10/a-scalability-roadmap/