You can self-study through PPL, CPL and IREX using Bob Taits books!
I did all mine in 2002/2003 using Bob Tait, and his books were the best by a long way.
If you can't self study for PPL and CPL you should consider a different career.
ABSOLUTELY! This would be THE QUOTE for this thread!
The learning never stops:
At a charter/instructor level, you should be familiar with the CARs/CAOs and AIP (as well as your company Ops manual).
If you want to get into the airlines, you'll have to know more than you ever wanted to know about your particular aircraft systems, FCOM (Flight Crew Operating Manual), as well as at least 3 other company specific manuals, etc.
Sure, you do ground courses on all this, but unless you have an effective study habit, you wont get there.
So...
Acquiring good study skills/habits while you're learning at the GFPT/PPL level will pay off over time. If nothing else, you'll save hundreds of dollars while you're getting your CPL/MECIR if you self-study instead of going on a course.
My 2c,
DIVOSH!