Why don't most microscopes use a 30x eye piece for greater magnification?

Most microscopes do not use a 30x eyepiece because higher magnification can lead to a decrease in image brightness and clarity due to the limited amount of light entering the eyepiece. Additionally, higher magnifications can amplify optical aberrations and reduce the depth of field, making it harder to focus on specimens. Most standard microscopes are designed for optimal performance with lower magnifications, typically around 10x to 15x eyepieces, which balance detail and usability effectively.