I'm confused on what exactly you are claiming can be faked. Anyone can get up in front of a class of kids and talk, barring people with extreme public speaking phobias. It doesn't make them effective public speakers. Nobody can get in front of a room while being evaluated and fake being a skilled teacher, and to even suggest that is offensive to good teachers. What they do is not easy, it's an amazing and valuable talent, and it sure as shit isn't something that can be faked on command. It's like saying anyone can get in front of a camera and fake their way to a Daniel Day-Lewis performance. Silly.
And as far as the frequency of evaluations, it's all relative. The point is it'd be a million times better than the seniority-based system we have now, where demonstrably bad teachers won't get fired for it. You think it's "horrid" that someone should have to prove they're worthy of holding a job that requires specific skillsets. I think it's a no-brainer. Teaching children is one of the most important jobs on earth, and you talk about it like it's unskilled labor that should never be scrutinized.