I am not talking about the justification of the SoloQ.
First and foremost, there IS a shortage of Tanks and Healers. There is no way to paint it pretty or pretend that there is some “hidden group” somewhere escaping the statistics. Its simply a fact.
With that out of the way, you dont need to be a mathmatician to know what happens in this situation. You need 1 tank, 1 healer and 3 DDs to make a group.
If you only have 10 tanks, 10 healers and 100 DDs… the result of that has to mathematically equal to: 10 groups MAXIMUM. And 70 DDs with out a group.
Back to SoloQ. If the problem is waiting in Donorgal to form a group (this is the established porblem).
How would SoloQ solve the issue? Lets put it this way:
LFG today: 10 tanks, 10 healers and 100 DDs
SoloQ tomorrow: 10 tanks, 10 healers and 100 DDs
Or… lets say you got both. Then its the incentive problem. Are you 100% sure that the tank/healer distribution wont be like this?
LFG: 9 tanks, 9 healers and 40 DDs.
SoloQ: 1 tanks, 1 healers and 60 DDs.
Because this dosent solve anything either.
That is why this:
Is key.
You always say that. And yet, you always come back.
Accept that you like to argue. Like me. And thats it. 
There is nothing wong with that.
If Blizzard’s policy depended on us, or we were about to cure cancer maybe. But we are just wasting our time here for fun. No other reason.