> In two months recently in the US, I never hailed a cab, but used an app to hail and track a car.

I haven't hailed a cab in years -- rarely
need a cab. If I needed a cab a lot, sure,
maybe I'd get a cell phone. If some Uber
app was a lot better, still, and I wanted
to use Uber, then I'd get a smartphone.
I live out in the 'burbs -- deer, ground hogs,
etc. in the back yard -- where the cab
service sucks.

> I track site analytics and app sales on my phone

The times I try to read graphs of data, usually
I copy the file of the image to disk, read it
with Microsoft's Picture and FAX Viewer,
and zoom in a lot:
Commonly people who draw graphs like the visual
aspect but come close to just ignoring the
axes and commonly have the text way, way, way
too small -- I can't read the text at all
without about 3X zoom. It'd be worse on a
smaller screen.

So, you are using a smartphone to read data
and less to write it. To draw a graph, I
use Excel and scream bloody murder until I
get out my notes on what the heck hidden
magic ways to left/right single/double
click to get the standard things done, e.g.,
get the font sizes up about 4X, make as
much as possible black and bold, etc.
It turns out that, then, I usually, for the
people I tend to show graphs to, print
the graphs on paper.

For photos, it turns out that I bought
for about $2 a digital camera -- cute
little thing, sold shrink wrapped on
a card. Apparently it has the camera
guts of a smartphone. It also has a
USB socket. And, yes, Microsoft PhotoDraw
will read an image from a USB port.
So, I can take and print some images.

But, soon, I saw that my sack of Nikon
camera equipment, especially with
my Honeywell smart flash, takes
much better pictures. To develop
the pictures, I just take the film
to Sam's Club or Wal-Mart. Sadly
their scanning resolution is much lower
than my pictures deserve, but otherwise
I get good pictures. Sure, someday
I will cough up $10,000 for a new
bag of Nikon equipment but with
CCDs instead of film. I'll get a
copy of PhotoShop, a color printer,
etc.

No joke, smartphone cameras (with some
interesting principles of optics on the
advantages of such a small lens,
short focal length, and number
of pixels per inch in the detector)
are no doubt now taking each year,
maybe each month, more photos than
were taken in all the history of
film cameras. But the quality is
like old snapshots.

E-mail on a smartphone? I won't do it:
To me e-mail is important; I have some
good ways to handle it; and those
ways make good use of my PC and its
software and won't carry over to
a smartphone. I won't put my e-mail
in a smartphone silo but want to
keep it on the same computer as
all my other important data --
data to/from e-mail needs
a big fraction of
my collection of all my data.

So, right, for some of the easier, read-only
work on a PC can move to a smartphone. And
a smartphone has some new hardware that
permits some new uses.

But, replace a PC? Not for any very
serious PC user. But the A16Z piece
kept comparing with PCs -- and that's
about as relevant as comparing with
lawn mowers.

It was just such a really good story --
a PC is a computer, a smartphone is
a computer, a lot more smartphones
are being sold than PCs,
some relatively light work done on
PCs can be done on smartphones,
a smartphone can also be used for
some new work that needs the new
hardware, ergo,
now the newsies and A16Z
have a story --
smartphones are changing everything,
including PCs. Nonsense. It's
just a tricky, deceptive story.

And that's a lot of what the OP
had to say: A lot of that data
was interesting, but, net, smartphones
are no more replacing PCs than, say,
an electric bicycle can replace a car.

A lot of tacos are being sold, more than
PCs, but that doesn't mean that tacos
are replacing PCs.

My simplest point: Mobile is not replacing
PCs. Some people don't like me to
say this, but it's just dirt simple
that I'm correct. That you like the
big monitors on your PC is part of the
best evidence -- until there are some
suitably good special glasses
those big monitors will remain a
big reason mobile devices won't replace
PCs. Then there's the mouse, the keyboard,
the printers, the old software --
dirt simple argument.