A lot of people have forgotten that iMessage was really the original killer app for the iPhone, as a side effect of how terrible US carriers were in the late 00

A lot of people have forgotten that iMessage was really the original killer app for the iPhone, as a side effect of how terrible US carriers were in the late 00's early 10's. You used to get a handful of txt messages a month, basically no MMS messages a month, and if you went over you got an overage fee, and still had to buy the 20 message package. MMS messages were more than a dollar each! But WiFi had become common both in the office and at home, and there wer unlimited data plans (with no SMS or MMS) that could be bought for reasonable prices. iMessage bypassed the carrier tax, It's that simple. That's why it became popular, and that's why the network effects working against Whats App, Signal, and others are so strong. And it's why there's skepticism towards the standards that Google and carriers are pushing for, because a lot of people don't remember the carriers' business practices very fondly.