It may seem obvious in hindsight, but at the time I don't think it was so obvious Wade was just a temporary hire. Parcells did leave late in the process and there weren't a ton of coaches available at the time, and at the time Garrett was considered a promising young coach. And let's face it, these days it's not uncommon for the owner to keep some coaches in place -- it's not like the old days where the head coach always hired an entire new staff himself.
Now after that season when Garrett got the Baltimore offer and then a raise to more than the head coach? And especially when all the assistants went to Miami and Jerry hired the coaches Garrett wanted over the ones Wade wanted? Yeah, pretty obvious then. But by that time it was too late.