If many miners move to another cryptocurrency, the difficulty for that network will go up, to the point that it's no longer profitable to mine it (electricity c

If many miners move to another cryptocurrency, the difficulty for that network will go up, to the point that it's no longer profitable to mine it (electricity costs exceed income). Unless the price for the cryptocurrency goes up as well, but it won't magically do that just because of an influx of miners. After all, those other networks don't have the utility that Ethereum has.