I think one crucial piece of the pricing puzzle is how much ongoing support is needed. If the theme or plugin typically requires a lot of support then the business is going to need annual subscriptions to cover it. However, if ongoing support is minimal then one approach is to gauge the average lifetime of a customer and price your lifetime package slightly higher than that.

Since lifetime plans are attractive to buyers, offering a lifetime option the first few years and listening and responding to customers is a good way to build a fan base. If the plugin is something that benefits from integrations with 3rd parties, then having lots of customers asking these 3rd parties to help integrate the new product also helps to get established.

I believe that keeping WordPress, themes, and plugins updated is essential, so "lifetime usage" without updates feels misleading to me and isn't really as attractive as it might seem to new users.