I think it is because they grew up that way. These days, everything is online, on phones, tablets, computers. It is easier to not have to interact with real people face to face or be physically active. And I think all of this, makes kids lazy.
My fiance and I watched the new Double Dare recently and were surprised by how much the contestants lacked urgency for the flags and prizes. We stopped watching and started streaming original Double Dare when contestants from the late 80’s, early 90’s and early 2000’s had urgency and wanted prizes.