It is still too soon to talk about a full-fledged revival of interest in altcoins or the beginning of a new alt season. The upside in ETH against BTC that we have been seeing is most likely a technical rebound after a protracted period of weakness in the ETH/BTC pair.
The 5-fold increase in transaction fees in the Ethereum network since the beginning of September is an interesting factor, but it cannot be unambiguously taken as a sign of increased activity or interest in the network. Moreover, the data shows a decrease in the number of active addresses in Ethereum by about 14% over the past week. Such a contradiction between the higher fees and a decline in user activity warrants further analysis.
As for Ethereum outperforming Bitcoin in terms of profitability, this may be a fleeting trend due to a correction after a strong fall in ETH relative to BTC. Ether has been depreciating against Bitcoin for a long time, and the current uptrend may simply be a technical rebound, and not the onset of a sustainable trend.
In order to talk about renewed interest in altcoins in general and Ethereum in particular, more convincing and long-term signals will need to be seen. This could include a steady upturn in network activity, higher trading volumes, or positive news about the development of the Ethereum ecosystem and other altcoins. However, for the time being the situation looks ambiguous, and it is too soon to draw any far-reaching conclusions.