Just look at Siacoin. Difficulty is not dropping despite losing $2-3/day net. I think plenty of people (myself included) would be more than willing to mine at a loss gambling that the price will go back up... Remember, it's not a loss until you sell.
SIA is on ASICs now, so it's not example.
https://obelisk.tech/Also SIA has infinite volume (there is no coin cap), so it is completely based on potential usability, not scarcity.
The same could be said about ETH (and not to split hairs but its infinite supply, not volume haha). ETH though is different though in the fact that it can have many different uses. The big problem I see with SIA is that its price is really going to be tied to the price of file hosting in the cloud, and the supply of storage space in the SIA network. What you have to ask yourself is, do you think the price of storage will get lower as time goes on? Can a decentralized group provide bandwidth and storage at a 1/10th of the price of Amazon (who has a massive economy of scale)? Don't get me wrong, I think SIA is a good idea and it will fill some sort of space. What I fail to see though is anything that will continue to drive the price upward. It almost feels like buying and holding tokens at an arcade in hopes that somehow they will be more valuable.