Subaru is having a good year. It's already having trouble meeting demand for its , and is selling like gangbusters. Despite that, people are still clamoring for more power in those models, pining for the days of the Forester XT and its turbocharged ilk.
By Doll's reckoning, adding the performance that people are wanting to cars that they're already buying will make the vehicles even harder to get at a dealer. It may sound weird for an automaker to actively avoid selling the most cars it can, but don't forget that in the grand scheme of things, Subaru is a small car company.
During his interview, Doll didn't shut down the idea of turbo models altogether, instead opting to leave the possibility open if interest in the basic models wanes and they need to juice up sales.
So, if you want a practical but turbocharged Subaru, buy a Legacy or start convincing people not to buy the cars as-is. Good luck with that though.