For those who say they should pay a portion - if I had to guess the actual bandwidth used for work (VPN, HVD), it would be a small fraction of my overall bandwidth use per month. Not really a good reason. If you compare it with vehicle use reimbursement, there's no wear & tear associated with bandwidth/electricity either. If they will just business expense it regardless, then consider yourself lucky.
I would have to say that really depends on the employee. Work provides me a hotspot, so I dont get any help on home internet. For years I would only use my work laptop thru the work hotspot. Any given month was at least 50GB according to the internal managed services "meter". Some months I hit almost 200GB.
With all the emails (and attachments), network file sharing, training videos, windows updates, chat programs, log collections (downloads / uploads), patches, etc....
For now I've stopped using it and put the laptop on my home network, but if Comcast ever starts enforcing their cap, I'm going right back to the hot spot because employer doesn't cover home internet. 15 years ago, they used to give us $30 per month to help, but once they rolled the hotspot, that was over