Chance are negligible. If collision occurs with a funded address, attacker you can transfer funds elsewhere.
Chances are still negligible when 1 billion people are using it? also can't I just run some kind of bots, that randomly generate addresses to see if
they have funds in them?
Yes, chances remain negligible. You could run your bot, but it'd be a waste of electricity. Chances are you'd wait the lifetime of the universe before finding a collision.