alphamale,
the plain and simple reason why TP operators prefer 1000 hour flying instructors is because they can promote them quickly to the left hand seat. 'Hands on flying ability' etc has absolutely bugger all to do with it. To fly as a captain on a multicrew aircrcraft you need to have a full ATPL. A requirement of the full atpl is 500 hours Multicrew. TP operators traditionally lose pilots all the time to jet jobs so not surprisingly they have a major probably recruiting and retaining captains. As someone else in this thread stated, teaching PPL's as an FI has diddly squat to do with airline flying.
Your really need to go and do some flying first before you decide a flying career is for you.You might actually hate it!