Airliners are up against physical limitations that don't incentivize upgrading. If there was an airliner that could fit millions of people and cost less than the 1980s version, I don't think you'd see many 80s aircraft around anymore, except in niece applications such as this computer. Perhaps now that we're at the end of Moore's law, you might see a larger amount of long-lived computers. But on the other hand, we'll probably find new ways to innovate in computing power.

Computers are still evolving rapidly. Instead of raw GHz increases, it will be things like tensor cores or other extremely-wide/GPU-type processing units. And of course, more RAM and more caches to feed them.