I have tanked all content and my answer as to why there are a lack of tanks can be found below:
1. Tanking drops in HM FPS are very rare. I ran 10 fps in one day as soon as 2.0 hit and I had nothing.
2. There is not incentive for me to join the group finder as a tank. With the abundance of DPS, why isnt there a system that rewards tanks? A drop that guarantees a tanking piece at the end of the FP?
3. I go in a flashpoint in BIS underworld and I pull the room, fight for aggro hold all on me, play the piano with my shadow and what does the healer do? He does damage, its good, I can heal myself, i got medpacks and cooldowns.
4. People do not respect the tactics and what needs to be attacked first. I do not go into the group finder to fight for aggro and compete with the DPS who attack other targets than what I tank.
5. I spend millions of credits / hours in my tank to have worse gear tanks perform better. So why should I continue to use my tank?
1.) It has an equal chance of dropping as any other spec's piece
2.) The incentive is an insta pop.
3.) But look what YOU did... It was awesome.
4.) The dps should not necessarily be attacking what you do... they should be killing weak to strong.
I love tanking in this game. I have one of each tank class and I play them all regularly in fp and ops. Sometimes I view my pug group mates as challenges instead of helpers. Crappy groupmates are just another challenge to overcome.