Somervile is an interesting case study because while he didn't need money from poetry, because he was a landed gentleman and country squire, he did need money in general, because his hunting lifestyle, easygoing ways with his tenants, and miscellaneous improvidence and prodigality meant that he was an epically indebted country squire. Really no poetry short of a coup like Pope's Homer could have saved him. In the event he's a pretty pure exemplar of the amateur poet, and indeed it seems suggestive that his most successful work, The Chace, is dedicated to describing genteel country sport.