I think this is on Apple more than anyone. They have the attitude that it's okay to break long-standing traditions for the sake of pushing society into the future. Apple users seem to be a-okay with this attitude, so I'm not surprised that it has eventually come to kick users in the ass.
The three years or so that they've been using the format by default is not enough time to catch up. I know this is the first I've heard of HEIC, and I'm sure I'm not the only one.
Apple should default to sending a jpeg in situations where it cannot confirm support of newer formats. Maybe this means jpegs remain the default interchange format indefinitely, but so what? They are Good Enough for most cases.
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