The larger problem here is that unless they plan to have their Google search results all say "click here to pay" or similar, this entire scheme violates Google's cloaking policy and should result in their being deindexed. This has traditionally been the entire reason that sites offered this workaround - it wasn't out of the goodness of their hearts.
Here's hoping Google actually enforces their policy.
Google doesn't want people having a bad experience on Google which would drive them to consider any other source for search. If a search turns up an article and preview and a click-through doesn't show the same content, Google users will be annoyed, which will drive Google to act.
Google's anti-cloaking policy, while presented as a benefit for users [which it is], is strongly in Google's best interest to enforce as well.
What I don't get is that they could just leave the first two paragraphs and let every see that, then require you to subscribe for more - google would accept that and they would still show up in search, right?
They could, but then only those two paragraphs would be indexed. That would make the content less rich, less relevant, so it wouldn't rank as high.
That's for the normal organic search results. I don't know the policy for showing up in Google news and the carousel. I suspect it wouldn't be allowed.
Edit: You can be subscription-only and be in Google news, but you have to show the same limited snippet to both Google and end users. And you get 'tagged' in the UI as subscription only. https://support.google.com/news/publisher/answer/40543?hl=en
That's what Experts Exchange was doing. Back in the days before Stack Overflow, EE was one of the hot places to go for answers to software engineering problems. It was a free site for many years, then one day they decided to require a subscription to read the answers. Google still indexed the question, so that you would open up a EE link, only to be greeted with "the answer requires a subscription". Google allowed that for a number of years before finally deindexing their results, but it took bloody forever!
From memory you could scroll to get the results IF it detected you clicked on a google search result to get there, otherwise the answers were not displayed.
Here's hoping Google actually enforces their policy.