As the author of sixteen novels I completely agree with your points. The biggest commercial mistake of my career was writing fourteen original books and only two novels with the same characters.
On the other hand, I’m very proud of the novels I’ve created. If today I had the choice of having written sixteen novels all with the same main characters and making a lot of money but not having written The Concrete Kiss, A Death In Beverly Hills, Death Never Sleeps and Death Never Lies or having written those books and having made far less money, then my choice is easy, that is to say, I would do the same thing all over again. But then, I never made my living from writing fiction, thank God.
— David Grace (www.davidgraceauthor.com)