I've been reading 3-10 books a year for more than 50 years so I have bought, borrowed and traded quite a few.
When I could afford it I bought new, for both the convenience and the shiny newness
I assumed right or wrong that those producing the books were making money from them and never gave much thought to it until all of the eBook DRM controversy.
I think that most who can afford it buy eBooks for the convenience and those who cannot borrow from the library unless they are truly unfortunate enough not to have a way to do that.
Most of the people I know are unaware or unbothered by DRM and licensing restrictions. And the heavy readers among them know it would not be convenient to have every book they have read on their living room shelves.
Those who are starting to read now are lucky IMO that despite DRM and licensing there is a reasonable chance that they can keep the books they buy, reread them if they wish, lend them to close friends and family members (there are legal ways to do this for most eBooks I think) and not have them take up space or be packed up to move etc. Such a luxury.
Helen