This just sounds like gating out content in a free to play gacha game unless you shell out per node so you're left with only being able to play under half a story chapter. If it's free you don't gate content.
What they'd have to do is make it free but with ads on sidebars, maybe a moving banner on the home page or manga page, and an ad at the start, end, and middle of a chapter (you can't have tons of them as then you end up like those horrible webtoon scan sites). If not that, then you make it a subscription service but you can't make it overly expensive like streaming sites or Marvel/DC's monthly sub. Publishers cannot be trusted to do either in a good way.
I mean, such a system could also include what Wuxiaworld adopted, which was to (1)
keep the first n chapters free, (2)
use the Wait-To-Unlock strategy (which meant each series could be unlocked daily and permanently) for the remaining locked chapters, (3) give free daily keys for doing basically anything (whether it be just logging in, or reading chapters - stuff you already came on the website to do), and (4) implement this alongside existing subscription and buy-to-unlock methods.
On top of this, if such a system then adds the normal manga publisher strategy of
keeping the most recent 3 - 10 chapters unlocked (depending on series), allows fans to provide translations in partnership with the author for series which lacks funding for official translations (this would also kill trashy, moneygrab scans), and manages to get multiple big-name authors and publishers to sign on, then I'd say it would be viable. Even better, perhaps allow translations between all languages for more market penetration and for more choice and variety given to people.
Give the consumers more options, and make the anime, manga and light novels more accessible.
Here's the thing: there's no way that these corpos would ever just let someone create a service with some ads or a cheap subscription, since the revenue would be relatively low -
they're the most short-sighted mofos out there, and are only concerned with the profits in this very quarter, rather than properly building long-term customer loyalty and a reputation like Steam. I say - if such a system works fine for Wuxiaworld, then surely it would be OK to at least try it for a new Steam-like manga platform.
I will end with a disclaimer though: I'm not any professional, so who knows if this would even work?