It's not a limit of resources in the sense of having not enough money. I think it's a limit of resources as in they aren't investing in a proper software development team for the D&D product line and not organizing the budgeting properly. Also I'm thinking they are located in the same building maybe even right near the R&D team for the game or something like that. If they had their independent budget and creative license to create the product independent from the D&D development guys you would see a much different result.
Does anyone remember the MTG PC game? Another flop of WotC in the software they develop.