Absolutely. I think living in a densely populated area, it can be hard to get a perspective for how big and largely empty the world actually is – and that's just land (and coastal seas, as far as LTE/5G reaches).
The remaining 70% are ocean, and people sometimes go there too! Some densely traveled oceans actually do have LTE coverage, e.g. parts of the north sea, since it has existing infrastructure in the form of wind parks that make adding a base station fairly easy, but that's the absolute exception, globally.
A single direct-to-cell satellite can cover a circular area measured in hundreds or thousands of kilometers. Due to the Earth's curvature, that's simply not feasible using terrestrial base stations.