You propose a purely technical solution. Somehow links that point to a paywall are marked as such by the system. As sometimes happens with purely technical solutions, this presents some difficulties, big or small. The main one would be knowing which links go to a paywalled site. You could have a list of them, but it would be hard to maintain it complete and up to date. Maybe there's someone out there who maintains such a list, but again it requires effort and, more importantly, it places all that effort on one single point.
There are other types of solutions that may distribute that effort more evenly on the community. Such as the one proposed by pureheartlover. Or maybe asking people that when they submit a link to a site they know is paywalled, to please include an alternate link. Maybe a suggestion in https://news.ycombinator.com/submit above the form. Or maybe readers generous with their time can comment with the alternate archive link (and maybe such comments can be pinned first).
This last one option is almost what we have now. Obviously, as most solutions that rely on the generosity of the community, it won't cover all cases and will fail sometimes to some extent -i.e. someone can still submit a paywalled link and it may not get the alternate archive link before you read it-. But, as an easy to implement and maintain solution, it's probably the best or close to it.
You propose a purely technical solution. Somehow links that point to a paywall are marked as such by the system. As sometimes happens with purely technical solutions, this presents some difficulties, big or small. The main one would be knowing which links go to a paywalled site. You could have a list of them, but it would be hard to maintain it complete and up to date. Maybe there's someone out there who maintains such a list, but again it requires effort and, more importantly, it places all that effort on one single point.
There are other types of solutions that may distribute that effort more evenly on the community. Such as the one proposed by pureheartlover. Or maybe asking people that when they submit a link to a site they know is paywalled, to please include an alternate link. Maybe a suggestion in https://news.ycombinator.com/submit above the form. Or maybe readers generous with their time can comment with the alternate archive link (and maybe such comments can be pinned first).
This last one option is almost what we have now. Obviously, as most solutions that rely on the generosity of the community, it won't cover all cases and will fail sometimes to some extent -i.e. someone can still submit a paywalled link and it may not get the alternate archive link before you read it-. But, as an easy to implement and maintain solution, it's probably the best or close to it.