As Sean and I have often noted here, the transition from ‘bogey’ to ‘par’ mustn’t be overlooked. Many of the famed sub-70 par courses in the UK (e.g Aldeburgh, Harlech, Rye) had historic bogey cards well into the 70s: Harlech’s bogey in the mid-20th-century was 76, with an SSS of 75, with only four bogey four holes (2nd, 5th, 6th, and 16th) and Rye was not dissimilar. Aldeburgh nowadays has 14 par fours and four threes, Rye has one five (the 1st), five threes and twelve fours, and Harlech has two fives, five threes and eleven fours.
GCA architects will tell me, I suspect, that any proposals for a card like that nowadays would be met with a fairly furrowed brow. As would the most famous card of all with two fives, two threes and fourteen fours (even if one of those fours is really a five)…