The same message produces different results depending on whether the person has heard of you. The difference is not percentage points, it is multiples.
Cold lists
People collected by a parser: they do not know you and expected nothing. The upside is volume — thousands are collectable. The downsides are low response and high risk: complaints about messages to strangers are the main source of spam restrictions.
Warm lists
People who have seen your comment, opened your profile, subscribed or read something. An order of magnitude smaller, several times the response, and almost no complaints: the person knows who is writing.
Which is cheaper
Compare cost of outcome, not cost of message. A cold list is cheaper to send to and more expensive in lost accounts and wasted contacts. A warm one needs investment first — and then works repeatedly, because the same list answers several approaches.
Turning cold into warm
The two-step shape: the cold contact does not sell, it brings the person somewhere you already demonstrate something — a useful comment, a channel, a teardown. The second touch goes to people who now recognise you.
Slower and markedly more durable: accounts live longer and the second step converts at a rate where the model closes. The first step is on the automation page, and the economics are in the lead cost piece.