It's not even just the raw power difference. One of the worst assumptions is that Toph could potentially instantly win because of Gaara's sand armor. But what they fail to realize, most people do, is Gaara rarely has it up. He only uses that technique when he's already being pushed, and he can throw it up on himself as fast as Ninjas use Substitution arts.
So the entire lynchpin of the argument, that Gaara is covered in Toph's element and there's nowhere to escape to, is bullshit. Second only to "Toph's bending completely overrides Chakra infusion and sentient spiritual possession because I said so."
And even if he were covered in Sand Armor, all he needed was a split second against Lee to get out of it, when Lee winced. Lee didn't even notice the switch. "But he wouldn't have a split second or warning!" Oh yeah, forgot, Toph doesn't even have to forcibly wrest control of Gaara's sand, she can just do it instantly as if there were no countervailing force or awareness at all. Of course.