The only thing is, that this kind of technical-only analysis (re: historical lows/highs etc.), is quietly assuming, that the rest of the circumstances are the same, as they were "historically" - and only the selected commodity values are different, and they "should", at some stage, revert to these "historical" values.
Which, IMHO, kinda misses the big picture. Which is; enormous debt overhang in the developed countries, regulatory/legal capture, preventing us from resolving the most pressing issues the RIGHT way, demographics, that won't support the current system(s) for too long anymore (in the West - in the East/Third World/Emerging markets, demographics is in a serious fookin' bubble - and as we know, bubbles tend to burst...).
So I don't know, maybe it is, that long term, these trends, tend to influence people in such way, that they in turn tend to elect the RIGHT people to the offices, and these right people tend to do the RIGHT things, after elected - but it is all very, very indirect, as you can see above.
And the immediate issues that we face, won't wait until people sober up - I think hard shock/collapse of the system is granted at this stage, and it really is uncharted territory...
While arable land/farms might go up&up from now on (that I think will be the case for the next decade, or decades - and legitimate, organic case for that - more people to fed on the planet), but the housing market - I do not think so. I think that we will rather see these house price/gold ratios going down, and well below historical lows - not necessarily because of prices continuing to fall, but gold will most certainly go up - thus bringing the ratio down again - and quite possibly, well below the historic lows). I mean, I cannot imagine worse fundamentals for housing bull market, nor I can imagine better fundamentals for metals bull market.