The use-case you describe as freelance writer or proper investigative journalism is the one place I expect targeted (and author curated) advertising to be able to pay the bills in the ideal market-fit theory. If as an author and "provider of opinions" you can't convince commercial actors in your niche to funnel value to you, I'd argue you shouldn't be writing non-fiction commercialy.

And in this not strictly commercial writing context, I believe client side mining may be a good form of low-commitment compensation.