I thought that 4 years was normal (at least in the US and most of Canada). Taking more than 4 years is very common.
There are a lot of opportunities at many, many universities. Various types of research and coops and internships are examples. Sometimes students do not want to graduate early since staying a full 4 years provides more time to take advantage of these opportunities.
Also, things like a change in major, or a class or two that goes badly, or a dual major, can stretch things out, regardless of whether the parents are paying.
Also, some majors have course sequences that need to be taken in order. Similarly, some classes are not available every year. These are however generally designed to allow graduation in four years.