The iPhone (and iPad Mini) obviously subsume the Newton --- so folks have a small pocketable device with them almost constantly.
The larger iPad works well for convenient media consumption, and with a keyboard and Apple Pencil, works as a sketchpad/notepad/creative device (and can be paired w/ a Mac via Sidecar) --- so folks have a medium-size device for a bag or coffee table readily available.
The Mac is available in multiple form-factors, from small portable suited for a bag/Starbucks/airplane seat table to small/inexpensive or large/powerful for a desk.
For larger media access there's the Apple TV.
Virtual reality à la the Apple Vision Pro is one lacunae --- but really needs software support, and a form-factor comfortable enough for folks to wear for lengthy timeframes, making the Apple Pencil suited to replace the Newton's stylus might be another.
I wish that they would standardize on sizes/proportions and connector types/locations so that accessories could be carried forward and only upgraded when they wear out.