I know that the idea has been discussed more than once in more than one way during the previous years and @Tut welcomed the idea at more than topic.
Since July 2014, @lubos has responded to a member with the following:
Now we have been waiting for almost 9 years for the inventory model to be added or improved.
Is this idea still under development and a solution will be considered by @lubos .
There have been numerous changes in the last 9 years. If you still have the version you refer to then also install the latest version and compare.
The inventory “module” is actually a series of Tabs that you can enable in Settings, this includes Inventory writte-offs that your quote refers to.
A good starting point is to review the Guides Guides | Manager and Scroll to “Inventory”. You can see what is available to manage inventory