The times have changed and the building block approach works very well.
It still takes the same number of hours if not less because the student doesn't have to work so long at the more advanced lessons.
The FAA has also started going in this direction as well after the dash crash and the studys which say the fundementals are lacking.
The jump in and let the student do everything does work with some students mostly young blokes. For the majority of the rest it produces pilots which may be able to hold it together but have little understanding in what they are doing. And will also take more hours.
When I started instructing my average was 6-10 hours in the circuit before solo when I finished full time instructing it was down to 2-3. The hours before entering went up from 4-5 to 8-12. About the same total time but they had alot more clue what they were doing.
BTW I was taught the jump in and do everything method and only really discovered what I missed when I did my instructors course.