IMHO, the touchbar had more to with competitive positioning against microsoft's touchscreen than optimising benefit for the user. It's the new 'one button mouse'.
You sure it was a reaction to MS?
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.
[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.