Nicely put, but then why need your example even be a pair of fancy glasses? It could be an energy generating device, or a transportation method, or a cure-all p

Nicely put, but then why need your example even be a pair of fancy glasses? It could be an energy generating device, or a transportation method, or a cure-all pharmaceutical or something. I think the answer is partly that you're right and that technology in the more general broad sense has particular tendency to keep improving in value; partly that the OP is right and your example has some unstated implications (these non-upgradeable devices might well be prone to competition and hence generate surprisingly low shareholder returns); and partly that there are some other factors beyond OP's, to do with how the goods are produced.