I was reading an article here about how Coles and Woolworths are now cutting brands and ranges in the face of the success of Aldi whose ranges are much smaller. It's not only Aldi; I have seen Australia Post concentrate on a large number of categories but small ranges in each. Unlike some people, they do not stock fifty types of paper clips.
The problem is customers want to feel in control over the buying process. They do not want to be pushed into a single choice but want to select the option that works best for them. The problem is people are coming to you with a problem; they want a solution. Like these people in the photo, they want a shampoo, if you offer them too many choices in a category, this decision making becomes difficult and complicated, next they get confused and often, then prefer not to make a choice, so they don't buy.
As a general rule in any category, three choices is perfect, four and five are fine for anything over six, is starting to get risky.
There are other advantages too, such as simplifying your stock control and better buying prices that you will benefit by reducing your range.
PS One trick that you may want to consider that is very successful is having one choice outrageously expensive. This high price will make the other choices look more affordable.