CKtalon
When it was still at the level of fan translators, I bet the range of readers was still less widespread than now? And the readers back then were probably a specific group of people who were already familiar with Chinese webnovels to begin with. The only way for them to access the translated Chinese webnovels was by specifically searching for it, maybe via NU.
After the Webnovel app, the audience has become more general than before. They probably got to know the app from recommendations based on their downloaded apps or something like that. I know that was how I got to know this app. I downloaded Wattpad and Webnovel was in the list of similar apps. This kind of general audience is still unfamiliar with this kind of practice (Privilege program). So they need to be guided. Or educated. Webnovel couldn't just launch the program assuming that everyone will automatically get it.
Another thing, when it was still at the fan translators level, then that was just that. Fan translations. Translations brought by volunteers who dedicate their free or spare time to share their passion with others. Readers are more inclined to support fan translators monetarily, through donations, or as you said the Privilege program on Patreon, even with the exorbitant prices, because the idea was that they were doing something for others voluntarily. Webnovel is different. It is a company. Translators here are not volunteers and readers are not mere readers anymore - They are (paying) customers. So of course their attitude towards the exorbitant prices would be different, especially when they are putting on their customer hat. They will want to get value for their money.
So Webnovel needs to up their game and provide better service to their customers.