If you rule out captchas, try limits, lockouts, et cetera... then yes. You just have to brute force the plain text string.
However, that does take time - at the very least, it's bounded by the rate at which the server will respond to login requests. Even if the developer doesn't add any measures to prevent brute forcing, the server itself can only go through the encryption + verification process so quickly, and can only handle so many parallel requests.
That said, this is why it's important to
- As a user, use a strong, hard to brute-force password
- As a developer, have adequate measures to prevent brute-forcing of your login process
Hashing and salting passwords isn't to protect against people who brute force the natural login process (there are other things that protect against that). Instead, they're to protect against potential compromise of the password storage itself (e.g. someone dumping the contents of the database).
Both hashing and salting serve to decrease the speed at which someone with access to the stored passwords can retrieve the plain text string they'd need to be able to go through the natural login process (of your site or other sites, given that passwords are commonly shared between sites) without tripping anti-brute-forcing security measures.
