Ask HN: What's a better solution for file sharing/management in a small company

We are a small team of 10 people with very mixed skills. We need to share content daily and we're frustrated with our current file sharing solution. To date, we've tried OneDrive (ok, but grinds Mac CPUs), Google Drive, drive sync also laggy / buggy / down more often than not - with these two, I'm never sure if my latest changes did really propagate, or what will happen if two people edit the same file at the same time and overwrite each others work through sync.

I'm seriously considering pushing the team toward managing all files in a Github repo, although expect some backlash from the sales / non-tech people. Is Github for file sharing a terrible idea? What other alternatives should we consider? How do larger orgs manage this chaos?