If the door is still sold, you can buy the unit and just replace the slider. Wasteful, but easy. Have you checked to see if the manufacturer just sells the doors without the frame? If the doors are older and were common in your area, you might be able to ask neighbors if anyone replaced one and still has the old one that's functional.

My doors are 42 years old, and when the rollers failed, I asked around on Nextdoor since these same doors were used in every house around here, but never heard from anyone. I finally managed to locate new replacement rollers after a long search.