[jl6]

Commercial, perpetually licensed software isn’t always free of future cost. Even if it’s only $50 today, you might also be on the hook for:

* Mandatory upgrades when v1 ceases to receive security patches.

* Mandatory upgrade of dependencies when a new version drops support for, e.g. an old OS version.

* Having to buy a replacement anyway when the vendor walks away from supporting the software (and why wouldn’t they? They’re not being paid any more).

* Or alternatively, the vendor doesn’t walk away from support, but charges you for it (effectively becoming SaaS anyway).

* The cost of running your own hardware to run the software. Dropbox is the obvious example of this - redundant offsite storage hardware is a hassle that you can outsource with the SaaS option.