Yes, it is possible to indefinitely renew the E-2 visa as long as the E-2 applicant continues to meet the requirements for the E-2 visa, including keeping the business running and maintaining the investment amount the E-2 applicant needs to invest. Generally, the renewal involves proving that the business is viable, and the E-2 applicant is still playing a role in running the business. However, it is still a non-immigrant visa and while it can be renewed an indefinite number of times, it is still not a permanent resident visa.