The touch bar was not a bad invention. Apple just neglected it and never gave it the software support it deserved. With some proper development it could have been great.
Consider the most basic usage of the touch bar, displaying function keys. The tactile feedback of a physical function row enables most people to touch-type the function keys from home row. For IDEs, NLE/DAW workflows, UNIX terminal setups and cross-platform software, the touch bar had nothing to offer but downsides. And even in apps that supported it, there was no unified mnemonic standard that enabled you to use the touch bar strip without looking away from the monitor and losing sight of your content. Apps that copied the content into the touch bar were even more hilariously cornered into bad UX, displaying a postage stamp-sized status for whatever you're working on.
The common defense of the touch bar says it needed hardware reworks and greenfield HID architectures to succeed. But I think Apple realized it was a totally flawed concept, and iterated on it internally to the point that they realized it was a sunken cost fallacy.