I highly doubt that Apple plans on converting the ENTIRE line to touchscreen.
If Apple goes ahead with this it will probably be a standalone model or you'll be able to add a touchscreen as an option.
It's not something for everyone, but here is my perspective as an artist.
I work in the movie / TV business and storyboard my projects. Basically I draw boards for every shot and then make an animatic in Premiere/Final Cut set to music or a temp dialog recording.
Currently I have to carry around a MacBook Pro AND an iPad Pro.
I plug my MacBook Pro into my monitor, where I run Final Cut and then draw the boards on the iPad. Since this is a creative process you end up going back and forth many times, tweaking the edit and either redrawing boards or creating new ones, as the cut changes.
Working on a separate Mac and iPad is a PIA and really inefficient.
I draw the board on the iPad, then airdrop it to the Mac. On the Mac I have copy it from the AirDrop directory to the NAS where the bin for Final Cut project lives. Data management is a disaster as you are basically working on two separate computers instead of a single system/NAS etc.
Could I cut it on the iPad? Of course, but in my experience jumping back and forth between programs and sharing data on the iPad is a lot more awkward and difficult than on a Mac.
There are other issues like not having access to programs on the iPad like full Photoshop, Poser etc
On a big project I used to run out of storage on the iPad, but since have upgraded to a model with more RAM.
That's aside from the fact that I have to carry both and iPad and MacBook Pro when I do this outside of my office. When I have to go through TSA at the airport I have to keep track of two devices etc. It's a lot of weight, bulky and a serious annoyance. It's also expensive. I had to buy a MacBook Pro AND an iPad Pro for another $1000
At one point I was so aggravated with the whole process that I almost switched to something like a Microsoft Surface or one of the other Windows laptop convertibles. But I can't really do that, because my whole company is based on the Mac and so is the rest of Hollywood.
What I really want is a MacBook Pro with a detachable screen that functions as a tablet/iPad that I can draw on.
That way I can have the main body plugged into a big monitor running Final Cut and I can just draw on the detachable screen like it's an iPad. AND I get to run full Photoshop and have access to all the other software that is not always available on the iPad like Poser.
I can see the logic behind Apple's thinking. The ergonomics of poking at a laptop screen are awkward, as it's tipping over etc. I get it.
But that's the wrong way to look at it.
If the screen is detachable it suddenly becomes two separate devices. Basically it separates into an iPad AND a MacBook Pro. Heck you could even run your favorite iOS drawing program on the detached Mac screen, essentially turning it into an iPad. The screen has a battery pack and can also be powered via USB-C or a MagSafe type connector for long sessions.
With that design you are working in two different modes.
Most of the time you are treating it like a traditional laptop and not poking at the screen. Why would you? You have a trackpad or mouse.
Or you're working the same way as you would with a separate MacBook and iPad, except you have the convenience of them sharing ONE file system and it obviously is a single machine.
When you're done they recombine into one neat little package.