TBH, MBA trackpad failures are often caused by liquid damage, bright spots on the display are caused by pressure on the computer when it's closed, and the wifi again is an uncommon failure that can also be caused by liquid (the wifi/bluetooth chip is near the fan exhaust on the back of the top case, which can serve as an entrance for liquid). I'm not saying that all the issues you had were caused by user damage, but they may have been, and they aren't part of any larger trend with known failures.