Store of value:
1. fundamentally stable
2. low inflation rate

Thus, ETH is not a store of value.

Its not stable:
1. Big source code with many more bugs than Bitcoin.
2. It is the driver of the ICO bubble that could finally burst hard which could also hit ETH itself hard.
3. Blockchain growing at a crazy speed and growth speed will even increase much much more if only a few ICOs deliver.   This is not sustainable forever.

It inflates too much:
Imagine the burst of the ICO bubble leads to a bear market but ETH market cap finally recovers after 5 years. Then one still lost 50% of value thanks to 100% inflation.

A store of value by definition has to preserve its value in the long term.