I think it is more likely because people are ****ed about timing belts.
They have been around long enough that a big group of people have found
out that a $39 tune up is required at a 100,000 miles, but a $600+ timing
belt is required at 60,000 miles. And when the belt brakes, it causes
major inconvenience. I do not think anybody makes an interference fit
motor anymore, as they had to warrantee replace a bunch of motors. People
find out a motor requires a $700 fix at 60k miles, they go to the
competitors car.

even more nonsense - any performance motor will be an interference fit motor
as you call it - how could it not be and get decent compression - econobox
motors for little toy cars don't need the performance and can afford the
extra clearance but check ANY car you consider to be high performance - BMW,
Audi, Corvette, Porsche, Lotus, Ferrari, Bentey, you choose -