Old fashioned reciprocating steam engines died out because they're very inefficient, heavy, and they burned coal so not at all clean either.

But we still use steam power. It's just that these days, we use steam turbines, which are much more efficient at extracting energy from fuel. It's still not clean energy unless the heat source is nuclear (or sometimes solar), but modern power plants burn a lot less fuel to produce a given amount of power than the old steam engines did.