Have you used any modern RSS reader recently like inoreader, they load the content of the page without visiting the publishing website. So still, no ads.
I'm happy with newsboat[1]; but I'm not surprised that people have integrated scraping into RSS readers.
Fundamentally, that's not a problem with RSS, that's a war between scrapers and content providers. If the email newsletter model persists long enough, I'd expect that people will come out with "newsletter readers" that scrape websites too.
I'm not sure there's a good long-term solution to the problem. Aside from constant vigilance (obfuscation).
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Earning a living from ads for these types of people.is not sustainable. They will have adblocker installed, so you are also wasting respurces with no income.
RSS or newsletter or whatever scrapper, it's there today already.
Issue is that Google Ads and such don't offer this and you don't get the "typical" ad networks.
If RSS were more popular there wouldn't be a problem to build the required tooling.
Even when feed readers don't send cookies etc. while fetching you can do a permanent redirect to a feed with an unique ID in the URL and most feed readers will store that URL, thus you can do tracking (incl. personalizing URLs in the feed) and all that.
What saves reader privacy currently is the small user base.