There was a lot of speculation as regards the bullish future for platinum in the early 2000's, both for industrial use and as a store of value, and so the price went through the roof. The appeal as a precious metal has never really become entrenched and a more realistic view of industrial use has taken over. Palladium has proved to be a more effective catalytic converter for car exhausts (look at the price graph over a few years) and I really wonder about platinum. Its not saying "buy me".
Silver has been more lack lustre than I imagined; its the poor cousin for jewelry but has consistent industrial use. It caught fire around 2007/8 but then collapsed in a heap. You need to catch it at the beginning of the speculation journey.
Gold is in my opinion is both a currency and a store of value, but subject to considerable up's and downs as the fear factor waxes and wanes. I think it will do well as the US dollar wanes over the next few years.
The question you need to ask about gold is this: If reincarnation was true, and if I was able to leave my assets to myself, but the new life would only happen in 500 years time, what percentage of your assets would be in gold? What percentage in real estate, and what, where? Etc, etc.