You have a smartphone, you have a tablet, and you have the PC.
Except some people don't have the PC. Instead of engaging in productive activities that work better on a PC, they do without. One user predicted that this would happen in five years, but it's happening now.
the laptop too big and heavy and uncomfortable
Even a 10" laptop like the "netbooks" that were in fashion from 2008 to 2012?
Jobs even did the mandatory car analogy - the PC is a truck - a very versatile vehicle that can do tons of things, but to be honest, there are times when a car is far better.
To complete this analogy, someone who can use a car most of the time and only occasionally needs to do these "tons of things" can rent a truck, such as a moving truck from U-Haul or a pickup truck from The Home Depot. Is there a comparable PC rental ecosystem?