You could write a custom system for tagging certain content to git commits using git notes and then write a batch script to fetch those files from some other service based on your current local head. Of course then the system you pull from would need to have versioning which at that point you are back at perforce/svn etc. If you don’t care about versioning your content then yeah, you could map dropbox/google drive to your content folder. You would lose versioning and dropbox/google drive both charge monthly fees for large amounts of data.
So I guess what I’m saying is if I were you, I’d just stick with perforce. You are most likely going to have to pay no matter what, it might as well be for more perforce space.
Besides, Perforce is free for 20 users / 20 work spaces with no other restrictions. We use it happily for years different projects and have introduced P4 to several of my customers to replace their old dropbox workflows and give piece of mind.
Seems interesting but it doesn’t help.
Perforce require a server to rent, and this too. The fact is that I had GitHub (free and already in use) and OneDrive/Google Drive (not free but I’m already paying for those).
I ended up creating a virtual machine on azure, so I can at least shutdown the machine when I don’t need it for long time.