All commercial software is rented. It's already been created and the marginal cost is Zero. You are ostensibly paying for bug fixes and new development, which is at least partly true in many cases. SaaS at least admits a rental model.
Free Software is rent-free, but development may be slow.
Wrong. You're conflating on-prem and SaaS commercial software together as "rented", when the former can be delivered as a perpetually working product whereas the latter isn't.
FOSS isn't free to host, accessible to users of all experience levels, doesn't necessarily include support, and isn't guaranteed to have a license that isn't hostile to its intended use.
Free Software is rent-free, but development may be slow.