Nobody who has even the slightest knowledge of cryptography will ever attempt to guess a Bitcoin private key that way.
For an P2PKH or P2WPKH address where the public key has not been revealed, the search space is 2
160; and there are approximately slightly fewer than 2
96 valid keys per address.
If the public key is known, it has a notional 2
128 security level.
An attacker would not try to guess the key by bruteforce. Rather than bruteforce, an attacker would use something like this free, open-source program:
And even if someone wanted to try bruteforce for some ridiculous unreason, there are about 2
256 - 2
128.3457 valid private keys, not exactly 2
256 keys. That is a negligible difference; but if one wishes to count keys, count the keys properly!
Technical information must be accurate. The good cause of teaching the public about Bitcoin’s security is not helped by misleading explanations and misinformation.