Well, it was always true for EMs that you could have a junior dev quietly spinning their wheels and not asking for help. The difference is before you could sometimes see they were frustrated, and they could see other people asking for help and know that's just part of how you work. If they can't see it passively, you have to proactively show them.
You can and should still have those 10 second conversations. We've got Slack huddles, screen sharing, VSCode Live Share for more complex pairing... the tools are really good now.
That said, I tend to agree, a remote culture that doesn't respect the need for teaching and mentoring is going to be bad at it.
When I worked in an office it was much easier to casually ask for quick help. It was often pretty obvious whether a senior engineer was busy and focused or between tasks, checking email etc. and the overhead/friction of these ten-second conversations is higher when you have to wait for a response on slack, then launch a video call, share screen... instead of just making eye contact and saying "got a sec?"
You can and should still have those 10 second conversations. We've got Slack huddles, screen sharing, VSCode Live Share for more complex pairing... the tools are really good now.
That said, I tend to agree, a remote culture that doesn't respect the need for teaching and mentoring is going to be bad at it.