Performance increase did not stop; smaller, better designs. The exponential is just a bit lower.

We don't realize it, just as someone using a text terminal may have not realised it between 1985 and 1995, if every response after a key press was already instant.

For typical GUI interfaces, tasks like tossing video data around, and so on, computers became approximately inifinitely fast sometime c. 2005 - 2010.