[edit: rewrote a badly written subclause to be clearer than before]
Your suggestion would address spam, but as major newspapers end up paywalled that's largely a non-issue. The others are moving to compulsory social login (e.g. FB) which also mitigates that (and basically makes you "pay" with your personal details).
Newspapers should totally have an easy feedback form, possibly even a dedicated forum, but not comments.
I believe the parent means that you pay/it hurts your wallet (even if it is $5 per year). When you "pay" via your facebook details being shared, then this cost doesn't affect you. If you cared you woulnd't be using FB in the first place :)
I could be wrong - I don't know if those accounts are able to comment or not.
I'm experimenting with a fix for this at repowcha. There's probably a cost threshold past which it becomes unprofitable to post bad comments with an agenda.
I'm not trying to be snide, but I genuinely believe you are underestimating the overwhelming drive that is caused by spite.
It's a sweet idea, but I don't think it's at all in line with how people think/utilize comments sections.
The idea of selling things online was never about how to sell them to people who don't want them. You're clearly not the target market. It would be for people who are so fiercely loyal they don't think twice about how nice of a bonus it is to be able to be in the select audience that CAN comment. I don't know if people are this loyal to publications, but I've certainly felt it towards YouTube personalities that align with my thinking so strongly that I feel supporting them is promoting my values.
To support the content producer. Maybe $5 is too high, but what if it was $2 or $3? I pay that to a few producers.
The Athletic, for example, has its own comment section (duplicated on a much larger scale by Reddit discussion of quotes from the paywalled articles). Even niche outlets like the Dunc'd On Podcast come with their own Discord.
The lure, I think, is basically what's being discussed here.
Sports discussion ... suffers perhaps more than average from an absence of moderation, so a paywalled community is seen as a benefit.