Indeed your Steam account is not transferable so when you die your games die with you.
The reason Steam gets away with it (for now) though is they’re unusually chill about everything. Give someone your account? They don’t care. Pirate their games? Don’t care. Make a Steam app mod that literally automated the piracy process and uses Steam’s own servers to get the game files? Cool. Pirates are also using Steam’s servers to play pirated games online (through spacewars, easily detectable)? More power to you. And in the midst of all this they introduce the family feature where people can share their games with others in the family.

But I am no Steam shill and the license has the final say. So always BUY your games (from marketplaces like GOG) when possible.