You might very well be right that this is what will happen.
And yes, it would be bad if native advertising increases dramatically because everyone has adblockers.
However, the problem I have with your argument is that it rests on preserving something bad and to keep something worse from happening. I think that's generally not the best approach, which is why I'm not 'conservative' in most of my views.
Let's say web content suddenly becomes infested with native ads. Those of us who care, might actually start paying for paywalled content. Those of us who don't, happily read advertising dressed up as proper content.
Or maybe the bigger publishers will not be able to exist anymore, and content becomes either really shitty, or really good with little middle ground. Perhaps we'll finally start paying those individual journalists and writers through donations and crowd funding.
I think a good comparison is music. People started ripping their music, so the industry replied with DRM. People cirsumvrented this, and the DRM became increasingly intrusive. Then downloads and torrents happened. All seems lost. And what do you know? 'Paywalled' music actually starts sort-of working. This may very well happen to video and text once companies get their act together and go with the tide rather than swim against it.
I've been a pretty extreme 'modern', tech-savvy consumer for most of my life. And yet, now that I reached my thirties, and now that I have disposable income:
1. I pay for The Correspondent, a Dutch, pay-walled web-only publication that has been doing well and produces great content by great authors, including some of 'celebrity' journalists here (and soon to be released in English, too).
2. I occasionally buy single articles from any of the newspapers in Holland through Blendle, at prices of around 20/30 eurocents, with the option of a refund that I rarely use.
3. I pay for Spotify, not just because it's convenient, but because it offers (or used to offer) a really nice interface for discovery and curated playlists.
4. I buy ScreenCasts and (e)books direct from programmers/writers in my communities.
5. I've donated to a number of arts/journalistic crowdfunding projects.
While there are many bad things that could happen, I'd argue that the current state of production, consumption, and accompanying advertising is already pretty bad. I'm fine with either: 1) the current models crumbling, and new models coming up that might be worse, so that it might get better quicker, or 2) fighting the fundamental problems and actively working towards a better alternative, or 3) hoping that the changes will end up better altogether.
But preserving a situation that is already pretty shitty just out of fear for something shittier seems like the worse possible approach.
I do realize that I'm leaving out the moral arguments in favor or against bypassing DRM, pirating content, or blocking ads. That's a difficult and perhaps important issue too, but I'd say judging by current behavior it's largely irrelevant to what actually happens.