>>18608031>It has a hit rate of 70%, and guess what? When you need it to 'just hit and KO them', it never fucking does.Learn your fucking statistics.
If your opponent double teams while you attack them, you will miss them both times (with a 100% accurate attack) only 10% of the time. You have a 45% chance to hit them once, and a 45% chance to hit them twice.
For three turns, you have a 67.5% chance to hit at least twice. If you can 2HKO a double-teamer, evasion loses to you in the first three turns more than 2/3 of them time.
Okay, you switched out to what you think is a more favorable matchup on the turn your opponent used Double Team and lost a turn of momentum? I admit that your chances have dwindled by then, but you'll still hit them at least twice in three rounds 38.6% percent of the time, have a 50% chance to hit them exactly once and miss them every time in 11.4% percent of cases. If your switch-in can OHKO or counter evasion, your chances are still pretty good.
Do note that this doesn't factor in leftovers recovery, which is one reason why I didn't calculate this for more than three turns. Your chances are also considerably worse if you rely on naturally inaccurate attacks like Focus Miss, which are punished the hardest by evasion users.
In conclusion, Double Team is not a consistent strategy for most Pokémon, even where it's allowed.
Now you're going to say muh Minimize, Simple + DT and Magic Bounce Espeon. The few common exploiters of those are easily recognized and you should have brought and conserved one of your ways to deal with them up to the point they come into play.