99.99% of electronic alternator regulators pulse-width modulate the field current, making the power dissipation in the transistor moot. Linear regulators are never used by oems; only in a few after-market specialized regulators, like Leece-Neville.
However, I have some experience replacing vibrating-point electromechanical regulators with more modern over-the-counter electronic ones in boats, aircraft, and tractors. The electronic ones are much more reliable, regulate the battery charging voltage better, and are less noisy than the electromechanical ones. You can get a generic electronic regulator at an auto-parts store for about ~$20.
However, I have some experience replacing vibrating-point electromechanical regulators with more modern over-the-counter electronic ones in boats, aircraft, and tractors. The electronic ones are much more reliable, regulate the battery charging voltage better, and are less noisy than the electromechanical ones. You can get a generic electronic regulator at an auto-parts store for about ~$20.