Drones do the heavy lifting. Many copies of each drones conciousness is fed into the collective to live digitally. There's a flow of information between the drone conciousness and the digital consciousnesses...It's just a question of how fair the work load is upon the digital conciousness and what a vacation inside the collective is like? or are there copies of the digital conciousness constantly forever on holiday who feed their life/memories into all the other consiousnesses?
Doesn't sound too much worse than 70 years reliving your memories in the Nexus.
What would happen to the (some) Borg if they got trapped in the Nexus?