The 2016 MBP's may have been designed, but Apple did not need to ship them.
More importantly, Apple did not need to also ship the 2017 MPB, the 2018 MBP(s), or the 2018 MBA. If they didn't have any alternate designs in the pipeline (why is that?), they should have reverted back to the 2015 design, with new parts.
Maybe? I don't think you're wrong, but I think all of those have reasonably easy explanations if you assume that Apple genuinely believed they had a good design that just needed some tweaking to correct, and I think they genuinely believed that. There weren't new designs in the pipeline that used fundamentally different keyboards. There weren't designs in the pipeline that went back on "all you need is USB-C." (I wouldn't be at all surprised if they stick with that, actually; it's conceivable that the 16" MBP that's rumored as their next release will add back an SD slot, but I'd be a little surprised if it adds back a USB-A port. I also expect it to continue to have a Touch Bar, although it may add back a physical escape key.)
> if you assume that Apple genuinely believed they had a good design that just needed some tweaking to correct.
Well, that's the point where I'd call Apple's judgement into question. They should have put the breaks on new releases with the keyboard until they had a clearer picture of what was going on.
More importantly, Apple did not need to also ship the 2017 MPB, the 2018 MBP(s), or the 2018 MBA. If they didn't have any alternate designs in the pipeline (why is that?), they should have reverted back to the 2015 design, with new parts.