It was not a problem because everything was replaceable, blowing a power supply/amp was not uncommon and a parts bin was beside the workbench for both in & out of warranty service. Now maybe not so much. Car gear was expensive and designed to be rebuilt with class AB and low freq PWM power supplies. Now with class D I suspect they operate at higher freq and toss the bad ones in the garbage and replace them in warranty.I see electrolytic caps being used. The worst being in car stereo equipment.