Perhaps the trick is not to entirely equate rockets with airlines, but to think in terms of progress.
In the last hundred years, we’ve gone from poky, prop-driven, rattly transport planes all the way to the Dreamliner (progress in range, passenger capacity, speed, comfort and efficiency).
Computer technology also, gone from rare brick-machines that could only display text, to phones in our pockets that are orders of magnitude more powerful.
There is no doubt rocket technology will follow a similar pattern, even if it takes longer than Mr Musk keeps promising (probably will). Nobody is denying the difficulties of rocket travel are limiting factors, but we can’t possibly predict what will happen to rockets and their usefulness in the next century or two.