I think respectable papers would go out of business if they followed suit. They are usually respectable because they dont rely on a outside organisation for funding, but instead rely on creating good journalism people want to pay for.
The Guardian would surely qualify as somewhat respectable and still paywall free...(I pay for it anyway, given I read it pretty regularly. It's only publications I read articles from maybe 3 or 4 times a year I have an issue with signing up for - would have no issue with a one-off payment if it was easy enough to do).
I assume you have multiple subscriptions to respectable newspapers and magazines because you care about society, right?
That said, the answer to your question is 'no'. If respectable newspapers and magazines followed suit, they'd disappear.
The cost of production of extremism/misinformation is much lower then it is to do investigative journalism or fund bureaus, or send teams out to physical locations to report. Fact-checking costs money, editors cost money. It all adds up.
The paywall model exists in many respects because if you are reliant on advertising as primary means of revenue which does fluctuate. A solid subscription base offers stability and predictable in which to run a viable organization - if you can pull it off.
That said, most of these paywalls are not 'hard-paywalls' where you need to subscribe immediately to read anything. They are typically 'soft-paywalls' where you can read a few articles before being asked to subscribe. From that perspective, your argument falls flat.
If respectable newspapers and magazines cared about society, they'd follow suit, and give the extremists some competition.