According to SuperData, there have been 772,374 subscribers to ESO as of June. If all of those subscribers renewed their subscriptions beyond the first free month, Bethesda and ZeniMax would take in $11 million a month. However, the number of subscribers who have opted to keep paying for the game has not been disclosed.
The report also notes that ESO is challenging perceived market trends, as subscription revenue from MMOs has been decreasing since 2010, but they speculate that the influence of ESO has already caused other new releases to embrace a subscription-based model, and there will likely be more of them in the future.
It remains unclear whether Bethesda and ZeniMax will maintain the subscription fee, but the online debate continues.