Trying to get a job offer in Canada by contacting employers and trying to get them to apply for an LMO for you is hard but not impossible. Of course also depends on what field you are in and if that field is in demand in Canada.
Many of the people on work permits are also recruited through agencies. Yes, you can say what you want about agencies but if a Canadian family wants to hire an live-in caregiver and they have no contacts in a country where a live-in caregiver might come from, they go to an agency. The agency will advertise for caregivers in some country and some of those will end up in Canada. Now, maybe the agency will make them pay for the privilege which is not allowed in Canada but if some people are willing to pay to get the opportunity, the agency gets away with it.
Same for non-caregivers. Say I have a business and I need welders, electricians whatever, if I can't find one in Canada, I go to an agency. The agency will advertise, possibly in some country where tradesmen are plentiful and make less money than here and I will end up with qualified employees. Some Canadian employers also look for people from countries that have a working holiday visa agreement with Canada. That way, they can get their employees without much paperwork and if they want them to stay at the end of the year or two, they can think about an LMO.