Are tanks/heals broken? Or am I just unlucky?

[Reibees]

Maybe I am unlucky, but I seem to frequently be having to summon yellow carby and tank AND heal for most groups.

In all but two of the groups I have been in, the tanks and heals have died, both on bosses and minor trash.

I'm wondering if there's something wrong here, are the tanks underpowered, or are healers? I'm really quite confused, because I shouldn't be tanking, healing, AND DPSing in every dungeon. Now and then with a newbie heal/tank or someone who was bad? Yes, I'd understand that.

..But every one of them?

I'm only lvl 28, does this get better later on? Is it only because tanks/heals have no clue what they're doing this early into the game?

I'm losing the ability to tank/heal/dps at the same time the higher level I get, so I'm dreading higher levels.

EDIT:
Okay people clearly aren't comprehending what I mean by me tanking/healing.
I don't just decide "well gee I'm gonna try to tank/heal", I only do one or the other if the tank/heal dies; if both die, I become both. I don't just go into a dungeon with the mindset that I'm an offtank/heal?? Seriously guys come on.