Even the most powerful .22 air rifle is no match for a .22 long rifle, not even a .22 short. A .22 air rifle pellet only weighs about 15 grains and even if shot at supersonic speeds, the high drag slows it down to subsonic within five or ten yards.
Also, a quality air rifle can cost more than a firearm, why should they be cheaper, the firing mechanism is far more complicated, the barrel has to be bored just as precisely. Most low cost air rifles are cheap because they are er, well, CHEAP. Plastic parts, bad triggers, etc.