This is not correct when consider Electrum seed phrases, which are different from BIP39 seed phrases.

Electrum seed phrases do not contain a checksum, but do have a version number encoded in to them. The version number is the first (usually) 3 nibbles (12 bits) of the SHA512 hash of the seed phrase. For the sake of non-2FA segwit wallets (which is the default wallet which Electrum will produce), these first 12 bits must be 0x100.

Given that these are 12 bits, then there are 4096 possibilities for these 12 bits. So by brute forcing one word to one of 2048 possibilities, there is only a 50% chance on average of finding a word which satisfies these conditions in the entire search space.