Starting a startup to replace Google Translate wouldn't be a simple proposition. Google's translation algorithms are considered best-of-breed and involve highly sophisticated statistical machine learning trained over a significant portion of their web crawl corpus data. Their staff scientists and engineers working on Translate are some of the best in the field, and the complexity here should not be underestimated. That said: yes, there's very obviously an opportunity here for the right team; but that opportunity is so big, its been there this entire time, even with the Google Translate API around.