16 GB is now small by modern smartphone standards, unfortunately. Your hardware is obsolete. It is what it is. The minimum memory size on new non-budget smartphones is now 32 GB, and on the balance of things, the correct trade-off has probably been made to keep making progress rather than maintain perfect compatibility with older hardware. The technology and industry is still evolving so rapidly that your phone does become obsolete in a few years. It's not stupid, it's a logical consequence of the rate of progress. All sorts of technologies on automobiles went obsolete very quickly within the first decade after the invention of cars, too.