I agree that this is probably the cultural solution, provided the author can't be coerced to post on Arxiv, but it's an ugly one, which reeks of an ivory tower

I agree that this is probably the cultural solution, provided the author can't be coerced to post on Arxiv, but it's an ugly one, which reeks of an ivory tower and gatekeeping ("nobody who isn't an established scholar in our tradition is truly capable of our work"). Perhaps this is better seen as a substantial defect in the fact that the academic web-of-trust model implemented in publication is based on quality of source (e.g. journal's prestige, or the submitting scholar's prestige) rather than quality of scholarship (e.g. whether a critical mass of researchers, rather than 1-3 anonymous reviewers, find it compelling and 'sign off' on it being good work). I hope (and suspect) that whatever emerges or is developed to replace the paid journal model of academic trust is designed to handle these situations gracefully.