Since bitcoin uses cryptography algorithms to create private and public keys there is a possibility it could repeat.
Person 1:
L54w...KraG -> bc1...kq4
Person 2:
L3mV...JU8G -> bc1...kq4
So could person 2 single handedly sent bitcoin from bc1...kq4 to a different address. My question is would both of the private keys work to change the funds. If so how will his affect bitcoin as a whole.