Generally there’s nothing in-person provides them that proper management in general does not. You’d both be looking at code anyway, on a screen, so pair programming is the same no matter the distance.
And there’s also the fact that experienced hires tend to not want to always baby juniors anyway. They need to learn how to read documentation and spend time on writing code. That’s mostly it for the first few years.
The most amazing programmer in my team, who is a loner, is 5-10years behind on the promotion ladder (against his desire).
You might be from a different era :-)
IT is a mass employer these days, there is no "not cut out of the field". Companies need software. They'll be bad engineers, but they'll be engineers regardless.
If your company's chat rooms are great, the onboarding might go well. Otherwise there's a big difference between noticing your boss/buddy is looking at their phone or having another kind of break and sneaking in a question or vice versa, noticing your junior dev's frustrated face, and looking at the green signal next to their name and wondering if it's a good time for a call.