Raptors are the new engine class used on starship and the superheavy booster. They're very new, but they're already rolling out version 3.
Look at how they've reduced the size, weight and complexity, while reducing cost and increasing thrust. The new Raptor 3 doesn't even require a heat shield to protect the neighboring engines.
They're reportedly able to produce these reusable engines for about $250k. That's like two orders of magnitude cheaper than some single-use engines.
Getting to orbit (or to the moon or mars) is going to get very cheap, very soon. And that changes everything. Imagine a rocket that can lift 200,000 pounds to orbit, then fly again a week later.