I worked in a office in late 1990s/early 2000s when it transitioned from Novell NetWare on DOS and Windows 3 to Windows 95 and 98 on the internet.
People using the internet on their work machines added so many problems:
- People spending a lot of time on shopping or porn. (This was before Facebook, and I don't think MySpace was around or popular yet.)
- People downloading and installing software they shouldn't. Which ranged from pirated software to adware to malware, or even something benign that conflicted with the tools they needed for their job. (This was mostly fixed when we migrated people to Windows 2000.)
- Viruses.
- People set up file sharing nodes for music and porn.
All of these problems came about once we added access to the internet.
Admittedly, it should have been rolled out differently, perhaps using something like Windows NT with firewalled networks.
But giving people access to the internet just allowed a lot of people who were naive to shoot themselves in the foot and waste a lot of resources fixing their computers.
But I would argue that the internet has made people far more productive in many ways. Especially software people!