Hey guys... I just did some homework on this, so here goes...
The Bronze Age came pretty early in human history (about 3000BC) because the two metals in bronze, copper and tin, are both relatively unreactive (ie. more likely to be found in their pure form) and both have relatively low melting points. Because of this, very little technology was required to extract them. For example, to get copper out of its mineral malachite, basically all you need to do is stick it on a fire for the copper to be smelted down.
The Iron Age came a bit later (about 1000BC) because it has a higher melting point than copper (or tin). These high temperatures couldn't be obtained with the technology available before that time - but with the improvements in furnace technology and invention of bellows, the high temperature needed to extract iron from its ores could be obtained. (Also, the discovery that iron+carbon=steel was important, because pure iron is too soft and corrosive to be very useful. "The Steel Age" would be a better name.)
In the modern era we've developed new, higher energy extraction methods that have allowed us to extract other metals especially aluminium. Though aluminium is a very common element, we had to wait for the invention of the electrolysis separation technique before we could get it out of its mineral, bauxite.
Future:...??? New alloys discovered, more recycling? I would actually say that in the future we will become less dependent on metals and more on plastics, ceramics, composite materials etc. We'll probably develop better methods of metal extraction though, using lower grade ores(ores with a lower concentration of the extracted metal). This question is basically all about the development of technology.
And to answer vulgarfraction's question...
We need energy to extract metals from ores because while they are minerals in the ores, the metals are not (usually) in their pure form but are parts of ionic compounds. For example, the aluminium in bauxite is actually aluminium oxide. To extract the pure aluminium we need to break the ionic bonds holding the aluminium and oxygen atoms together, ie
aluminium oxide ---> aluminium + oxygen
Because the bonds are strong forces of attraction between the atoms, we need large inputs of energy to negate the effect of that attraction and break the bonds.
Most of this info came from Chemistry Contexts. Hope it helped