Why would prokaryotic cells be considered a simple cell when compared to eukaryotic cell?

Prokaryotic cells are more simple and smaller than eukaryotic cells. Prokaryotic cells are structurally more simple because of their small size. It's also defined as the smaller a cell size, the greater is its surface to volume ratio (means surface area of a cell compared to its volume).

In smaller prokaryotic cells, a large surface to volume ratio is present. It means that nutrients can rapidly and easily reach any interior part of the cell.

The large eukaryotic cell have limited surface area as compared to its volume it means that nutrients cannot rapidly reach to all interior parts of the cell, because of that eukaryotic cells are more complex than prokaryotic cells, and they require specialized internal organelles to carry out processes like provide energy, metabolism and transport necessary chemicals throughout the cell.