This accounts for around half of US employees and most US businesses. In the UK and other countries, it's even more.
> all electronic onboarding anyway
That's not true, you'll almost always be having in-person chats throughout your on-boarding if you're in the office. And anyway, the tech really isn't the issue here. As a new recruit in the office, you're usually sitting near your mentor/line manager. Every now and then they'll verbally check in with you, or you can tell them you're stuck on something and they'll tell you what to do or who to go to. As other colleagues approach your team area, your manager introduces you to them and explains what they do.
In a remote environment, all of this suddenly takes a lot more conscious pro-active effort. Check-ins have to be rigorously scheduled. New hires need to feel safe enough to approach anyone they need to, and to be told in writing who to approach and how. They need to be introduced to everyone explicitly via call or messaging. They need to be protected from falling "out of sight, out of mind", and encouraged to build personal connections with colleagues.