Tanking Shortage

Expanding a little bit about what I was talking about yesterday, I'm wondering why there is a shortage of tanks in the game.  There are probably a few factors that contribute to the overall problem.

• People are too impatient, and make the job harder than it has to be. I have tanked almost every instance from Ragefire Chasm all the way up to Forge of Souls, and I can't count how many times I've had other players "assist me" by pulling.  They do it with no regard to when I'm low on health/mana, or my taunts and abilities are on cooldown.  It's always my fault if I don't grab everything they bring me, all the while relentlessly doing damage and preventing me from gaining aggro.  Especially in leveling instances where some of the mobs may be higher level than me, and I get a miss or resist with an aggro causing shot.  And if someone's below 30% mana, and I pause for them to drink, I get, "Gogogogogo".  Then, they post the damage meters, so they can brag about how much they've done.  Every class has some form of threat management, and it's each person's responsibility to do the most damage they can, but back off when they start drawing attention.  Being a good DPSer is knowing when to back off and let the tank re-establish threat.  It's all these little things that make me prefer playing my warlock, following along in the back and throwing shadow bolts.
  
• People do not help new tanks gear up.  Each of my tanking capable toons that hit 80 has faced a major problem.  I can not start doing heroics as a tank right away, because there's no way I can hold aggro against someone who has ICC25 gear when I'm in crappy blues.  If I even try, I'm booted from the group.  If you want more people to tank, be more supportive of newer tanks getting better gear so they can better tank in heroics.  This is also a discouraging point, so I feel like I have to run and gear as a DPS spec first, and then start building a tanking set, which is what I've done on my paladin.  If you're a plate-wearer in the DPS slot, don't roll on defense plate when the tank needs it.
  
• People are ass-hats.  I've been in PuGs where I've been met with the must vulgar, rude and insulting party members you can imagine.  I don't put up with it anymore.  If anyone doesn't like they way I tank, or the pace I set, they go on ignore, I leave, and 10 seconds later I'm in a fresh instance while they're waiting for another 20 minutes for a replacement tank.  If I'm on cooldown, I hop on one of my other tanks, and I'll still be in a run before them.  I just refuse to group anymore with people who are disrespectful and mean-spirited.  You would think they'd be more appreciative and nicer after having to wait so long.

I think the bottom line is that tanking can be a lot of fun, and very rewarding, but every group has the opportunity for someone to make it a negative experience, and that's why more people aren't doing the job.