Of course, it is not now. It is a potential problem. When the number of Bitcoin accounts is large enough. It will be easier and easier.
It's a potential problem if/when quantum computers break elliptic curve cryptography. At that point, Bitcoin addresses which have been used to sign transactions or old P2PK outputs could be cracked.
It has nothing to do with the number of generated Bitcoin addresses, though. The chances of collisions are still
extremely unlikely.