By doubling the amount of gadgets in the market you are also reducing price of the gadgets (according to offer and demand). The parent's idea is not new, it was already introduced in the first chapter of Marx's Capital. The only capitalistic solution to the devaluation of work introduced by increases in productivity is to increase the demand for things: by increasing peoples consumerism via marketing, reducing the durability of the things, etc.

This vicious circle has to stop, or the planet will stop it for us. We should think about how to work less and consume less.