Maybe I'm just unlucky.. 
But regarding the advertisements, yes, I would say that they do
serve those purposes you've mentioned. However, if you were to
compare Apple with Dell, Apple definitely is more popular
especially among the Mac users. With correlation to advertizing,
Dell seems to advertize more than Apple computers. And I would also
agree, that their sales need improvement as compared to Apple,
which is more efficient than the former.
Since every computer users knows about Dell, Dell's purpose of
telling others about their new model or products everytime on the
newspapers (more than any other models) clearly shows that either
their product/model is always improvising as it it not efficient
enough, or they're lacking in popularity among most users.
I've got friends who were once owners of Dell computers or laptops.
Their main uses are just for homework or project purposes. From
their testimony, their computers don't last more than 2 to 3 years,
despite careful handling.
And back to topic, their technical support is also very
inefficient. I once tried calling the helpline and kept asking them
to send an engineer down to my home to repair certain componants as
I'm in doubt due to unfamiliarity. But all they offered was
phone-service and told me that they can't do it. Furthermore, they
asked me to go down to their place with my computer to get it
fixed. What kind of service is this?
Such unpleasant encounter has tarnished their reputation and my
impression on their customer service and helpdesk.
Like what the topic starter has said, I fully support his point of
view. I'll never trust Dell again, after I'm done with this
computer. 