@kwb2977,
I think nothing is replacing nothing. Few years back we thought laptop will replace desktops. But those who have laptops 50% of them have desktop also. They use laptop for battery backup, traveling, emergency tasks etc.
Same thing also for laptop vs tablets.
Only very small laptops can take place of large laptops. Like 9 inch or 10 inch laptops. But different people has different choice about screen size ... so nothing is going to replace nothing