AWS SimpleDB has been a dead product for years now. Afaik, nobody is developing it, nobody is advertising it, and I believe it's not been launched in any new regions in ages. Even internally, when I worked there, it was not a product you should use for anything.
Yet it's still supported. Customers are still using it. Somewhere, there is a team in AWS keeping the lights on.
Because AWS knows that customer trust is more valuable than whatever it costs to keep that product alive.
Google does not understand that.