Sometimes all you need is perseverance and some skills to start your own business. These days, internet will be your bestfriend as you can basically run your business at the comfort of your home.
agreed nowaday people can just run business from the comfort of home its unlike back then when starting business need to rent a place but it also means far greater competition starting out business not as easy as it is depicted by many people there's a lot of struggle not to mention the strategy needed nowadays are more advanced than before utilizing social media and many more.
so there's an additional layer of challenge here knowing the fact that competition is greater and much more people want to turn their life around through various means such as starting out these online business.
also, capital is still a necessity at the end of the day with the online business.
However for those who want to do something just to make a profit without wanting to develop or build their own business, of course there are those who do that, but they are very disadvantaged because currently doing business is the most profitable job, especially when there are many light businesses without capital that can be run.
most of the light business you mentioned proably are affiliator and marketers, yes it can be done online, just building your own online presence could attract many brands to take advantage of your follower base.
it does require special effort though also not all people could do this.