Why is the cytoskeleton within the cytoplasm a recent discovery

Cytoskeleton which is within the cell is extremely small. But later a discovery came out which enables it to be zoomed.
Cell Biologist discovered that organelles they do not float freely in a cell, but they are being supported by a structure which is within the cytoplasm. Cytoplasm is termed as a mixture of cytosol and organelles. The substance which is gel-like in the cytosol, all the other organelles, structures which are suspended in the liquid they make up cytoplasm.
The work of cytoplasm is to support its structures and also fill the cell. The cytoskeleton is termed as cellular which is contained within the cytoplasm and it is always present in all cells and gives cells a shape.