I guess probably some people want to accumulate and monitor the activity of as many private keys as possible, in the hope of being the first to be able to sweep funds if deposits are ever made?
Even if it's a big waste of time... (Not to mention that people who can keep a server running 24/7 to monitor addresses are generally able to generate as many private keys as they like, so I don't understand who could buy bulk of keys to OP...)
It reminds me websites like keys.lol and others.
1,461,501,637,330,902,918,203,684,832,716,283,019,655,932,542,976
This is the amount of total possible keys. Just to read this number requires a couple of minutes
I don't think that nobody will try something so stupid. even if you can have trillions of keys you have just 0,00000........000.....1% of the total number of keys. (I am busy now and can't provide the full answer).
How much resources this will requires? Moreover, ok you have one of these key loaded. What amount? What happens if the owner will move just after one block?
Completely non-sense. If something similar was possible, btc value was adapted just to... zero
. 
