In Quantum Leap, why did Sam never make it home? In the final episode he finally got to see what it looks like when he leaps. That shows that there were leapers after him. Wouldn’t it be safe to assume they knew more about leaping and returning as time went on? It just seems very implausible he would never make it back. I’m assuming it was done by the writers in case they wanted to add more to the series but it just doesn’t make sense to me. Why did Sam never leap home?
I've never watched Quantum Leap myself, but Wikipedia's description of the finale seems to explain it fairly clearly:
Sam learned from a bartender named Al ... that he was in control of his leaps and could have returned home whenever he wanted. The bartender reminded Sam that he created Project Quantum Leap to help the world, and that in each leap he changed people and events for the better. Although Sam wanted to go home, he instead chose to return and inform Beth that Al was still alive.
This strongly suggests that after informing Beth, Sam could have returned to his old life, but instead selflessly chose to continue leaping and helping other people. So essentially, he never made it home because he was too busy continuing to leap and perform heroic deeds.
Out-of-universe, Scott Bakula confirmed in an interview that, just as you'd suspected, the ending was written this way in case the series was ever picked up for another season.