^You can't expect anyone to do all that unless they go to 7 leagues a week, and @DOX, 20 matches vs. any deck...heck, the most I'll ever play vs. the same deck is 5 times, and that's only when I get REALLY bored at a BR and want to waste time.
Me, I try to build a new deck every week, so I can hardly seriously test them, if at all. If I look at the flood of decks some people drop at the Deck Garage, I see that other people do the same. I like to think that it keeps my gameplay fresh, if anything.
The matchups? They have nothing to do with playtesting. The most in-depth they ever go (if at all) is a guess because the other deck has Weakness/you have Resistance. Like that even matters. Yes Dusknoir is weak to T-tar and T-tar resists him, but that doesn't mean he can't win. Speed, power, recovery, bad starts (@the one who said you only count matches with "skill"..that's ridiculous. Sure, I could ignore all those matchups and have an almost perfect win record. Heck, while I'm at it, I'll ask the Judge at Worlds to ignore my losses because of bad starts. Why not?)...all things to consider if you want a so-called "educated" guess. With which you'd probably be the first. All match-ups so far are completely biased. I think the only way to ever get real estimates is a collaboration project, like DOX's thread on the metagame. Until then, I advise everyone to refrain from producing these ridiculous, biased guesses.