I was recently surprised to learn how professional photographers charge for their work. They charge for their time and expenses such as equipment rental, food, etc but the client never actually owns the IP. The photographer then charges a usage fee separate to their day rate and expenses. For example if its going to be in a magazine thats having 100,000 copies printed they would negotiate a fee for this and any additional use by the client would have to be paid for.
I see software companies as having a similar model where its pay per install etc.
What if independent developers were to adopt a similar charging model? Say I build a website for a company - charge for my time in building the site but then also issue them a monthly bill based on the number of people that have accessed the site. In reality I can't see anyone agreeing to it - but somehow professional photographers are able to charge this way.
In this article: https://fstoppers.com/originals/guide-pricing-commercial-photography-part-4-license-fees-8713
The author gives the example of the woman who designed Nike's logo and only earning $35 because she didn't have a license in place and at the time didn't expect Nike to become the company it has. It seems kinda incredulous to me that this person feels entitled to more money simply because they did a job for someone and was paid for it (presumably a fair amount at the time) and then because their business has done great they should be entitled to be paid more when they haven't really done anything extra to make the company the success it has become.
Anyhow the SaaS model, per-cpu, or per-seat models are pretty much equivalent to how photographers work. The clients own no IP and it's all usage based. Independent contractors can just set up a SaaS that has a one-time fee for customizations, in addition to the normal monthly price (this is usually the last option in the menu, "Call us for pricing").