It does look like a slow but steady decline.   A decline from 90 million to 65 million is very significant.  Still, the remaining 65 million units shipped per quarter are also significant. Obviously, people still buy PCs, but time might be running out for this product.

There is nothing strange about it− this is just the final stage of the same cycle all products follow:

Birth –> slow initial growth –> fast exponential growth –> a slow down –> death.

This is how almost everything works in the world, following the so-called S-curve (aka a logistic function) that looks like this:

The function was named in 1844–1845 by Pierre François Verhulst, who studied it in relation to population growth.  The initial stage of growth is what we call “exponential.” Then, as saturation begins, the growth slows, and at maturity, the growth finally stops altogether.

Even the most popular and famous products have followed the same relationship.  And yes, that includes products from Apple.  Look at the sales numbers for the iPad below. Sales are already declining (while I cannot imagine my life without my iPad!):

Same looks true for the iPhone.  Not only does each model follow the S-cycle due to the older model replacement, the entire product line that is now seeing slowing sales.

In fact, it looks like the entire global market of smartphones has reached its saturation and doesn’t grow much anymore.

The market is saturated with smartphones and, maybe, it is ready for some new disruptive product to replace them? Something like this futuristic phone from Total Recall, perhaps?

But, going back the subject of the PC decline: if we consider 1975-76 as the year when the first PCs were introduced, this 40+ year-old piece of technology still shows tremendous strength, resilience, has already made a lot of money for its inventors and manufacturers, and will probably serve us well for a few more years.