But, you never controlled what EVs they got. I could get a Rhyperior to take out most of your team. I'd give it 252 Attack and 252 Speed EVs. I'd give it a moveset like: Hammer Arm, Stone Edge, Earthquake, and Mega Horn, it would use Earthquake on your Rhyperior and it would probably die. Your Staraptor? Dead from Stone Edge. Your Empoleon? Earthquaked. EV trained Pokemon are powerful and are hard to fight against if your Pokemon aren't EV trained.
A Garchomp trained in Speed and Attack could basically KO your team. It's really fast with 130 base attack. If it knew Outrage, it'd take out 2-3 Pokemon easily. Your Pokemon do have EVs, but they aren't EV trained. EV trained means that you controlled what EVs they received to make them a certain way.