In office, there's watercooler chat that can lead to debugging session. In remote there isn't.
That being said, with the former culture, it's harder to ask question online and asynchronously, since usually they prefer and wait to have in face session instead.
The equivalent in remote is a chat/thread turn into a call with a screen share. Managers and seniors encourage juniors to ask questions or just “speak” their minds. There are multiple touchpoints for that to happen, dailies, 1:1’s, spontaneous check-ins b/c people care. In a culture where remote work habits are good, these will be imparted on new-joiners, especially less experienced ones.
That being said, with the former culture, it's harder to ask question online and asynchronously, since usually they prefer and wait to have in face session instead.