Steve Jobs: "I'm as proud of the things I have done as the things I have not". Jobs would not have brought this version of TouchBar to market; not a chance.[1]

[1] My source is my personal opinion and anecdotal. If I'm not unimpeachably correct in this assertion you should downvote; there is no possible means to prove the assertion so only judgement can decide the validity of my claim. While I had met Jobs and had multiple run-ins with him in Palo Alto (I was an avid walker and lived on Ramona for several years), I never knew him well on an intra-personal level.

Yes, but that can also mean that during that it was shelved as a bad idea only to be revived as a scrambled attempt to have a one-more-thing moment.

An 8 year release process lines up with the release of touchscreen-enabled windows 7 and 8. Sure, they may have been investigating it before the windows release, but the choice to produce this hamfisted feature, rather than a touchscreen, still looks like a competitive reaction.

Many things take lots of time to develop, and lots of things never make it into an actual release.

EDIT: khaledtaha's comment above sounds even more plausible, give the strategy Apple currently appears to be pursuing.