I fail to see how right-to-repair reform would have changed this situation. Tesla's fix was too expensive so the customer went elsewhere... and got it fixed. Problem solved.
This case is a bit tangentially related when it comes to the solution.
Sure, right to repair at it's most basic isn't going to make Tesla make this more repairable, or perform the repair in that way. Since they view the battery unit as a single unit, they don't have to sell component internal parts of the battery unit, or give instructions how to open it - they can just wave that off as a glues box never to be opened.
But - Tesla gave the owner a single option for repairing the car - replacing the entire battery. The owner saw that the batter modules, the groups of cells within the battery case were valuable by themselves - $12k versus the $16k Tesla was charging for a new one. But Tesla would not sell a new battery to the customer, they would only sell the service of swapping the battery, keeping the old one. Surely right to repair, forcing Tesla to sell parts like Batteries to owners, would get around the madness of Tesla keeping your old, damaged, but very valuable battery.
Right to repair would make it easier for third parties to perform repairs if they have access to schematics that manufacturers have. One could argue the cost would be significantly lower if Tesla provided schematics to third parties (whether for free or a paid system).
