Fact: it can and it does exist on its own.
For its existence, it does not require any building defects - such as higher ground levels, lack of drainage, leaks, defective pointing or plastering, the existence of cement plasters etc. It can occur in perfectly well maintained old buildings. As long as the walls are connected with the soil, the wall fabric over time wicks up moisture and diluted salts from the ground, eventually resulting in the phenomenon of rising damp.
Of course, any additional dampness problem adds to the problem of rising damp, "amplifying" its effect, making it rise higher.
The whole phenomenon of rising damp, although extremely complex, can be relatively easily understood and predicted.