how long you keep a car is your decision. if you like it, and you're willing to pay for regular maintenance, then keep it. this "long run" comparison of owning and repairing versus buying a new car is just silly. So many people have the incentive to get you to buy a new car, but practically no one has an incentive to tell you to take good care of the things you own so they last.
And new cars arent always better. That nice collision avoidance/lane keeper and camera system? that was implemented as a countermeasure for increasing A and B pillar size after regulatory agencies decided too many americans were getting crushed to death in roll-over accidents. collision avoidance was literally the only way auto manufacturers could keep you out of a manslaughter charge thanks to the absolute byzantine nightmare of info-tainment systems that also do things like climate control.
controversial opinion here but older cars teach you a healthy fear of operating a 2000lb rolling death machine. no infofainment means they are safer for the driver, and no nanny-state A pillars mean you arent doing 80 in a 65 quite as often.
I own a 2000 mercury grand marquis. its a v8 so it inspires me to bipedal transportation pretty often with its fuel enconomy. the biggest problem I have with the car is my coworkers nicknaming me "the don" for driving a murdered-out land yacht but its what i like.