Funny thing is: There's actually some pretty good Dungeons and Dragons games for PC. But you're deliberately creating a straw-man here. What Civ is doing is not even close to simply taking a board game and simply porting it to pc. It's taking elements from board games and elements from "traditional" computer games, and that mix seems to be working pretty well for CivV, as it's a very successful game that is constantly within the top played games on Steam. If there were a Catan game that did a similar thing it could actually be quite a fun experience. And whether they make up the settlers or use historical figures and put them into a pseudo-reality wouldn't change anything about how fun the game is.