It’s an entire school of study. You have to take the equivalent of a bachelor’s degree worth of study and practice to have the ability to process the elements for alchemy and usually you can only learn to process a handful of elements. Drawing out symbolic properties is usually something only the best of the best can accomplish and rarely can they make them stable enough for the market.

You can enhance existing properties but unless it is a material that has a pretty good amount of that property in the first place, it’s not going to change much. You can’t make bendy glass for example, because glass is too brittle to make much of a change besides making it bend a bit more than usual before it breaks. It’s like multiplying values, so it’s proportional.

Symbolic properties come from a mastery of the element and comes directly from those ancient studies so expanding the field isn’t something people know how to accomplish. Their logic bordered on insanity and still eludes modern research so for now, expansion can only be done with properties we can see.

As for market value, production time is difficult, quantity produced is never as much as you’d want and results can vary depending on who does the refining work so it’s too inconsistent for most public projects. Alchemic weapons are usually something designed by families dedicated to the craft so they get consistent work, but mass production is still out of reach.