Because you'd also have to submit the money it would cost to buy every combination, and also, you likely couldn't fit every ticket (tens of millions of combinations) with a realistic-looking ticket generation time (approx 1-5 seconds between each ticket created). i.e. if 50,000,000 tickets all had the same timestamp (or were off by nanoseconds) it would be a dead giveaway.
If you have this capability then why not just insert all number combinations into the db well before draw time?
Makes me wonder how money flows from lottery terminals back to the lottery itself. I imagine there's some rigorous bookkeeping involved.