I've been flying for about 4 years and the only time I remember when a PPL could have been done in weeks rather than months was sometime during the exceptional summer of 2003.
Summers aren't the best time, suprisingly, because of the haze. It's OK to fly with the instructor but he won't let you go solo.
During the autumn of 1999 or 2000 I recall booking a lesson every day for 3 months, and being able to fly only twice! The PPL took a year to do, due to the weather.