Hard to say. I'm not sure about "never be a good store of value" but in comparison shouldn't do as well as the ones with utility. Speaking of which, if I were to be investing for retirement 30 years down the road like your generation might be doing, I wouldn't invest in any crypto that are Proof of Work, like Ethereum. They will slowly become obsolete as more people realize it just doesn't make sense to have to consume huge quantities of electricity to ensure security in the platform, when other options like Delegated Proof of Stake (like Steem) exist and become more known. I wonder what would happen if some big, well respected name like Ben Bernanke comes out and says something like, "Well, I guess crypto isn't such a bad idea after all, but I sure as hell wouldn't invest in Bitcoin as long as they still use Proof of Work. Who thought that was a good idea"?