I even thought about how the coding shouldn't be so hard to do this, as the website looks at your unlock history already. It just has to look at your subscriber status as well. There could be two plans.
1) Account subscription for $15/month or $150/year. With some coding, there would be an additional button on the lock screen for subscribers to skip the lock screen on chapters. This will ensure that if the subscription is discontinued, the chapters readers haven't unlocked with spirit stones won't be able to be accessed.
2) Novel subscription for $1/month or $10/permanently. The same button could be used on that novel, or the lock screen could just be skipped for that novel.
This service would get rid of a lot of the negative vibes the spirit stone micro-transactions gets from website frequenters. Most people will spend the above amounts for a subscription, and even though the richer readers won't be giving as much money, the higher volume of subscribers will make up for it.
For example, A Valiant Life (https://www.webnovel.com/book/9067142506001505/A-Valiant-Life) has 4 million views. If only 5% go the subscription, that's $200,000.
What do you think guys? Do you think this would work and make sense for Qidian to do?