Even today, where there are a hundred different types of ball, good old-fashioned line and length bowling is an incredibly effective way to bowl: Hit the spot, do a bit off the pitch or in the air, take wickets. Simple.
Yet it's also a world of pain to do consistently.
Sure, you bowl in nets as much as you can. You put up with slogging batsmen and you take time to work on your action.
Then you get out into a game and bowl two four balls every over, wondering where it all went wrong.
What's going on?
It's not the puzzle you think, but it does take some work on your part. It's easy improve your accuracy (and pace at the same time) with a simple process.