I personally found it more difficult to find jobs at that time of year, being the beginning of the year, as most firms seem to do their recruiting for that 6 monts or so at the end of the previous year.
I'm not saying it's impossible to find a job, but at minimum it'd take you a week to search, apply, interview and start. I know a lot of people who couldn't afford to have a few weeks without income - and by people I don't mean your average student living at home with parents, I mean people who have to worry about rent and other expenses like family members they help care for or kids or things like that.
For some people yes it is just an excuse, but for others it is a genuine reason, especially if you are a UWS student forced to do summer school due to terrible timetabling lol
so you really don't have the time to job hunt in advance.