And just the same, Japanese people are not one unified blob and each have their own preferences regarding texting, just like the rest of us.
It's about defaults and majority/average preferences, not about "every single one does this" and it gets tiring to remind people otherwise, as if they don't know.
So even if there was such a thing as default, we wouldn't know it. Let alone from a foreign country that most natives don't speak a foreign language. How many Japanese relationships did you have to form such knowledge on the majority?
Last, but not least, it is not tiring to remind people to reframe the conversation. It is healthy and constructive.
But, I will say that to a greater degree than you perhaps would imagine, Japanese people by and large do know what to expect from other Japanese in minute contextual detail. And with that knowledge, they try very hard to meet others' expectations.
What matters for the analogy to be useful is if there are two big clusters in east and west. Not regional differences within the clusters, or between individuals.