Not necessarily. Substantiality is proportionate, so a smaller investment can suffice for a smaller enterprise, but a business that earns little makes the marginality question harder to answer.
The price that helps one test hurts the other
There is no fixed universal minimum, so a modest purchase is not automatically weak on substantiality. The difficulty appears at the second test. An enterprise available cheaply because it produces little income has to show present or near-future capacity to generate more than a minimal living for the investor and family, or a significant economic contribution.
The question to ask before making an offer is therefore not only what the business costs but what it produces and what it would produce under new ownership, supported by the seller's actual records. A Douro-Dummer contractor comparing a small operation with a larger one is choosing between two different evidentiary problems, and the affordable option is sometimes the harder case to make.