It's really very simple.
Ruger changed manufacturing policies to more modern methods. Specifically, they used to tool up for a certain model and then run a complete year's production of that model at one time, storing everything that didn't have a buyer in a warehouse. Then they'd tool up for another model and run that model's year long supply. In order to use this philosophy economically, you need to have a very good estimate of your sales for the upcoming year, and thus of the price point each model will sell for.
The change was to a more modern plan, based on the 'just in time' philosophy: manufacture each model just ahead of the next month's supply requirements. That requires a very flexible production and supplier line but is less expensive and less risky to operate.
Ruger recognized that the ROA required a larger set of unique tools and support equipment than other models, and they determined that the resources could better be used making other models. Using a 'just in time' philosophy for the ROA kept manufacturing resources tied up and not usable on better selling, more profitable models.
Bill Ruger's passing may have made the decision available, but what really killed the ROA, and what will likely keep it out of production, was the switchover to a new production line philosophy.