Also a former runner and I agree with you for the most part. But not all cycling miles are created equal. Mountain biking I’d say is 1:2 as far as physical exertion (for a hilly, flowy route). Uphill is probably 1:1, out on the flats… more like 1:4 (maybe more).
The physical pounding & impact is way more in running, which requires much longer recovery times. In terms of the physical toll on the body cycling is closer to swimming than running.