Making steel is not hard, as a concept. You add carbon in the process, in the right amounts, until you get steel. I’ve seen Youtube videos where they pull the sword out of the forge and rub charcoal all over it before pounding it and they repeat this process until they get the right combination.
It probably took a long time to reheat, rub charcoal, and pound which is why it would have been expensive.
The ancients had no idea as to this "concept." All they were doing was following a process that had been discovered by accident and then handed down for generations. Take ore from a certain mine (which undoubtedly was of a composition that suited to the process), then smelt it and forge it in a certain fashion, and you had a product that was "tougher" than most other irons.
There was a Bronze Age iron works in Anatolia (ca. 2000 BC) where a few steel objects have been found but these probably were just lucky flukes.
That's why some of the finest weapons from that era were made from meteorites, because iron meteorites usully also have a smidge of nickel. The stuff was so rare and valuable that the buried King Tut with a meteorite dagger.
The Chinese were quench-hardening steel by about 400 BC. By 200 BC they were tinkering with blending wrought iron with cast iron for better hardness. They had no idea of the underlying chemistry but what they were doing (without realizing it) was optimizing the carbon content of the finished product. It bears mention the Chinese also invented gunpowder by accident while trying to invent the elixir of life.
The Japanese method was born out of necessity because the Japanese islands have no sources of iron ore, only iron-bearing sands. It took an elaborate process that required decades to master to produce even a mediocre ore (unless I'm mistaken, the Vikings also had a similar problem but never came up with so elegant a solution).
The methods got more refined over the centuries and the product became more consistent but it wasn't until the early 18th Century that the element carbon was identified. That introduced science into steel-making and a bit more than 100 years later someone finally devised a scientific method for repeatedly, predictably and precisely controlling the amount of carbon in the steel.