Bootstrapping means a company spends what it makes. Its difficult to keep up with internal resources as it is not always practical for businesses that need a large investment such as manufacturers or importers. It would just unnecessarily waste their time when they could explore options and get help from outside.
Let’s say even if a company starts with just personal savings and runs on its initial revenue then it can take much longer to grow this company without investment and what’s the guarantee of wasting all that time and getting success.
The entrepreneur will probably not get any salary at an early stage when the revenue is going as investment in business. They will be likely not be earning any money for quite a while.
When personal savings are all spent and the business is still not growing then the entrepreneur can easily end up in a lot of debt.