There's no basis in that assumption. In fact, I'd argue that it's possible that this format (interspersed with graphics and with a user base tuned to ingest content in a certain way) may actually aid retention and understanding. Instagram users have gotten very good at quickly gleaning information from the format. There's a huge userbase and they are not likely carrying around a physical book or eReader. This book format is essentially on them at all times and takes advantage of the potential to "hook" a user at an opportune moment.

Instagram users aren't expected to "drop their habits". Their habit is one of consumption - this just fits into that habit.