Why are you always implying that the blink is bought as a first item after boots or something? It always depends on the situation and the game being played
You make it sound like buying blink on hero X is just flat out wrong, and that's not how it works. Having the ability to adjust to different situations is a huge part of this game
Also, you can make an argument for just about every hero you mentioned to buy a blink
There are definitely heroes where buying blink on them is flat out wrong. Hell there's lots of heroes where buying a certain item on them is flat out wrong, and if it isn't flat out wrong, it is pretty bad so it's effectively flat out wrong.
By that logic, you're saying that blink on AM and QoP is perfectly fine.