It seems like Iron age began 2000 years after the copper age... And there was the intermediate age of bronze... If iron is tremendously more abundant than copper...and certainly more than the tin alloy component of bronze...why the long delay in between? Was it the problem of achieving the high melting point of Iron?... Iron=2800 v Copper=2000? Thanks for your response.
The problem isn't the high melting point of iron (not the problem, but this does result in some problems) - it's possible to smelt iron (i.e., convert iron ore to metallic iron) at much lower temperatures, c. 1200C. However, this is still significantly higher than the temperature required for smelting and melting copper, c. 1100C. A small but significant difference - earthenware pottery kilns reach copper smelting/melting temperatures, but fall short of iron smelting temperatures and far short of iron melting temperatures. Compared to iron, it's much easier for copper and bronze technology to develop as a side-effect of pottery.
Since iron smelted in the solid state (i.e., below the melting point) comes out of the furnace as a spongy bloom that has to be consolidated, slag has to be expelled, etc., and then the iron has to be forged into the final product, there are some further steps that need to be learned beyond just smelting iron - the technology for casting copper and bronze are essentially useless for iron at this stage.
Forging itself is a very old technology, predating the smelting of metals, and metal casting. But early forging was cold-forging (gold, copper, iron (usually meteoric in origin)). For iron technology to become usefully competitive with copper and bronze, the two keys elements are (a) hotter furnaces for smelting, and realising that you can smelt iron in the solid state, and (b) hot-forging and forge-welding. While these certainly aren't impossible to develop, even accidentally, they don't appear to have developed quickly.
There is also a 3rd key element: (c) realising that iron can be a useful competitor to bronze. The advantage of iron over bronze is its abundance. High tin bronze alloys will be harder than iron, and don't suffer anywhere nearly as much from corrosion. Smelted iron doesn't have the attraction of meteoric iron as something that has fallen from the sky.
(If it had been necessary to achieve the melting point of iron for iron smelting to develop, we might still be in the Bronze Age!)
Some related discussion:
https://www.reddit.com/r/AskHistorians/comments/8538sf/how_was_metallurgy_specifically_smelting_casting/ (with a whole bunch of useful references by [deleted])
https://www.reddit.com/r/AskHistorians/comments/13vdgb/why_does_the_bronze_age_comes_before_the_iron_age/ (it isn't just about temperatures - see the discussion on furnace types by u/Aerandir and [deleted])