We have three seats of SW and three users. We are storing all of our files (>3000) on a server and accessing them with Windows File Explorer.
How much easier would our lives become if we transitioned to PDM? (Sorry, I'm an engineer...I can't help it. )
We need to justify the cost.
It is impossible for anyone to provide a useful answer to that question without an in-depth look at your specific use case and that person needs to have enough experience with Solidworks PDM to know how to apply it to your situation. Anything else will be someone's experience based on their use case which may or may not apply to yours.
...or marketing, could also be a response based in marketing.
Ironically, my response is based in my own experience for one unique use case.