You could not be more wrong in the first sentence of your post.  I'm sorry
your tooth died, but quite honestly, it was probably destined for that end
anyway. Crowns are done for two reasons: esthetics and/or function.  In other
words, they, like veneers, can be placed to cosmetically enhance a smile or
other cosmetic issues, or they can be placed because a tooth has been
weakened by current decay, or previous placement of fillings.  Yes, teeth can
die after being prepped for a crown, but in the case of a crown being placed
due to decay or failure of a previous filling, the nerve is already
compromised.  Most dentists will recognize this and either perform a root
canal prior to placement of the crown, or advise the patient that this is a
likely problem.  
As for your statement that crowns are a big money maker, my response is that
1: These are high quality restorations that, IF the patient takes care of it,
will last many years, even decades. Therefore, the fee is commensurate with
the service.  2: There is a lot of overhead in placement of a crown, which
includes a lab fee for the lab fabricating the crown.  
I would also mention that I have never seen a solicitation from an
organization or person trying to get me to attend a seminar to "sell crowns."
There is currently somewhat of a shortage of dentists, and I am busy enough
without having to "sell" anything.  I have been in practice almost 20 years,
and am not naive to the fact that there are unscrupulous individuals in my
profession.  However, in my opinion,  no profession is immune from such
problems.  I feel my job is to educate patients about the status of their
oral health, and help them make the best decisions to either maintain good
oral health, or improve it if necessary.  And yes, I do lots of crowns,
because that is still the best long-term solution for many of my patients.