Books like Myth-Fortunes

This was just a nostalgia read, coming back to a humorous series that I'd last been reading decades ago. It's pretty bad: dumb jokes, too-obvious wordplay, overly sentimental with really unconvincing moralism, strange sexism. But it doesn't aim high, and for all that it is fun in a dumb way. What surprised me was that, although the previous book I'd read was nine books earlier in the series, and written 14 years earlier, the characters don't seem to have grown one bit. I had expected the plot to be the same, but did not expect that the characters and their interrelationships would still be exactly the same. I imagine it takes some effort to put your characters in stasis over such a long period, so the authors should be recognized for that.