Yes, those are two important factors.
The lack of accessibility to a school is partly explained by the distance that students have to travel. Some communities are several hundred kilometres away from the nearest francophone school. So it is not reasonable to expect a student to travel four or five hours every day to go to school.
In addition, in some urban areas, such as Regina or Saskatoon, the schools are not really well located. Therefore, some students decide to continue their education in the majority language for reasons of accessibility, transportation and distance.