I recall my '79 Honda had a belt which if I had ever thought of replacing it, seems like it would have been a half hour job for a shade tree mechanic. LOL, I used to slip the belt of the camshaft pulley to try different valve timings, mostly advanced by one tooth, just to see how the torque curve changed (though I didn’t think of it in similar words). Those were the more carefree days for me, indeed!
I think one reason why car makers went to the belt was because that way they could do away with push rods, which often, in themselves, caused trouble, but mostly they just often “ticked.”