i think i was born too late to relate to most millenials
for me, big computer is for either
A. Something that needs more power (gaming, CAD)
or
B. Something easier to do with a mouse and keyboard (long documents, fps games, video and photo editing, etc)
but i have no problem spending $3,000 on something through my phone screen. I bet whatever business im buying from has a mobile-first design for their website anyway