I don’t know how much of a gun it was. Apple has definitely been working on RCS support for a year; you don’t add that in a few months. Similarly I’m pretty sure Apple has been considering USB C in iPhone since at least when they started working on the USB C on iPad, which is what 5 years old?
Of course without pressure they would have probably be slower to move forward, and with Apple secrecy it’s always hard to tell how long things have been ready to ship. But let’s not pretend they just woke up this morning with a horse head in their bed and told their direction team to start working on this.