Why was sodium not extracted before the 1800s?

Sodium was not extracted before the 1800s primarily due to the limitations of scientific knowledge and technology. Prior to this time, sodium was found in compounds like sodium chloride (table salt), but the process to isolate the element required advanced techniques that were not developed until the advent of electrolysis. It wasn't until Sir Humphry Davy successfully isolated sodium in 1807 using electrolysis of molten sodium hydroxide that the element was finally extracted.