with square rule there is no time saved by having a framed in ridge.

Think of it this way - if each mortise or tenon is a joint, to join the peak of one pair of rafters requires two tenons and two mortises or four joints. If you delete the ridge and join the two opposite rafters to each other, you only have two joints whether you are doing half laps, tongue and forks or whatever. And since the structural advantage of the ridge is minimal, they just deleted it and I bet the guys that worked through the transition were glad to see it go.

Let's look at the framed ridge's benefit when scribing a little closer in order to understand why they would hew or buy additional timber and cut additional joinery and think of it as a cost saver.

The mortises in the ridge were all laid out and cut by measurement prior to laying up the roof plane. The same is true for the notches in the plate. The plate and ridge were set the correct distance apart, leveled and square to each other. Then the rafters could be tumbled. The process is described in detail in Jack Sobon's series on building his barn in Timber Framing (somewhere around issue 80).

Without the ridge, you still have to tumble the heel to the plate, but you also have to lay up each pair of commons to mark out the peak joint.