Yes investment is for everyone because it is the best form of staying up and measuring up. Investment is a sure way of securing your future and that of your children. Going into investment does not mean you must have the whole money on earth before doing that. Check out the number of people that went into investment years back and compare them to those that never did investment you will see that everyone needs investment.
You're right, investment is also a way of gaining freedom in the future. Those who are looking for a possible way to gain freedom in the future should just start investing from somewhere. And surely, you don't necessarily need to have a stable source of income before investing, but the little income you're getting from side hustle is enough for you to get started no matter how small it is, because alot of people feel that getting started with investment that you most have a steady or stable source of income, the most important thing is having your discretionary fund available. Once you figure out that you have a discretionary fund there is no need of waiting to build a very large discretionary but to get started with the little you have at same time building your discretionary so that it won't run dry.