2015 Subaru Outback – Frame Rust: Repairable or Dealbreaker?

I checked out a 2015 Subaru Outback today and noticed a fair amount of rust/rot on the frame rails. I took some pictures but wasn't able to have a mechanic inspect it since l'm out of town.

I really like the dealer, they've been great to work with and they even said their shop would be willing to repair the rust before selling me the car. But I have no experience with frame rust, so I'm unsure if this is something that can actually be fixed properly or if I should just keep looking elsewhere.

For those familiar with Subaru rust issues, is this a common problem? Is frame rail rust usually repairable, or is it a sign to move on? Any advice would be greatly appreciated.