Two thoughts come to mind: 1) Has the government determined that a significant portion of the people who aren't voting cite polling booth hours when asked why they don't? And 2) Have they considered how this will change the polling booth security environment?
On the first point, I believe government employees are guaranteed a break to vote if their shift spans the polling booth hours. Can anyone confirm this? Or shed light on any private-sector policies?
On the second point, the longer they have to ensure the integrity of those ballot boxes, the greater their vulnerability.
Finally, if the answer to the first question is no, then the government could be wasting a lot of money, in areas related to the second question and beyond.