I have observed that most persons have more than 5 different jobs. If one job doesn't pay this week then the other will. That is what is in their mind. For instance, a man will be working as an engineer in a company, still a government teacher, also have a shop for small business and also a bolt driver. All these things just to survive.
Perhaps you would know other method that can help reduce multitasking
I purposely highlighted the first sentence as you used "most," how possible is that? Most jobs are time demanding and need your attention, not a divided one, so it's not easy as you narrated unless you are a shop owner in addition to what you do. Even if some people are doing it, it's a heavy burden on them and it will be a very negligible number of people that would cover much in a day, which will often tell in their health, and money is not everything. The time to do all that means that the person will have to work almost 24 hours a day without sleeping/resting as it's not easy to be actively involved in 5 different jobs, or should I call it occupations in just a day? Come to think of it, your main job is a paid one, and a job of that nature will take you between 9 am and 5 pm, even if you know how to cut your corners, you will still do an average of 9 am - 2 pm. Is it the remaining hours of the day that will cover up for the remaining 4 occupations? I don't see how that is feasible really, they will clash and will not work. Working three hustling together is still more feasible but likewise tasking and it depends on the nature of the job, while 2 jobs are better and common these days in Nigeria if one exempts farming from it.
However, this is not what we call multitasking, multitasking is the act of performing the task/job at the same time, better say simultaneously. You won't have to leave a vicinity before you multitask. I deem it fit to make this correction since we learn daily. Nonetheless, what you described is widely referred to as Moonlighting, but in some spheres depending on the job, it could be called Juggling.
It's so unfortunate the state we find ourselves in Nigeria, a country where Master's and Ph.D. degrees do not guarantee a good living not to mention of good retirement. As much as we citizens have our share of the blame, the government and their poor leadership have the most of it and have dragged the situation into a state of hopelessness. Gone are the days when parents were proud that their children went to school alone, now, people are starting to enrol their wards in outside schools extracurricular training like barbing, tailoring, engineering work, beauty house, furniture apprenticeship and other training and artisan works that were like a taboo for those who went to school in the olden days. I can't blame them since it's for obvious reasons that education has failed so many people in the country. Those extracurricular training are the plan B and there are some children that would have learned 3 of them before they eventually graduated from the university.
This is shameful in a country that is blessed with huge potential and natural resources.