"Despite their name, rare earth elements (with the exception of the radioactive promethium) are relatively plentiful in the Earth's crust.." -- https://en.wikipedia.org/wiki/Rare_earth_element
Even if REEs are more common than their name suggests, with current consumption trends we're going to face massive resource depletion shocks within two decades as crucial industrial elements run out. New Scientist covered this several years ago, and they made a great infographic summarizing the issue.
Things that glimmers like gold in phones and computers and wires, are gold plated. It's likely worth the time to pluck out the shiniest parts and save them in a pile. A pile that grows in value over time. And increases in value the larger it gets.
Gold plating uses incredibly small amounts of gold. You would have to have a huge pile, and spend a huge amount of time creating that pile, to come up with any noticeable value. Unless you're doing it automated, on an industrial scale, I very much doubt you can even get within an order of magnitude of minimum wage.
I remember a few years ago seeing a book of gold leaf on sale at an art store. Normally it was something like $80, but on sale, it was $30. I was wondering how they could be making money on that. I did the research and found out that a typical book of gold leaf only had about $10 worth of gold in it (at the time).
one of the most known italian chefs, Gualtiero Marchesi, is known for preparing gold leaf risotto, which while appearing as something only the fabled edonists of the 1% can obtain, is actually something anyone can make at home (and edible).
More seriously: permitting and infrastructure. Once you've spent a couple of years convincing people that you're not going to fill the water table with arsenic and you should be allowed to start building, you then realise that the mine is in the middle of nowhere and roads, railways, worker housing, electricity and water supplies all need to be provided.
