The Hoops boss faces a summer of uncertainty with key men such as Gary Hooper and Victor Wanyama on the radar of a host of top clubs.
Lennon has scoured the world to bring rough diamonds to be polished at Parkhead, but he fears that talent trail could reach a dead end.
The Northern Irishman will be able to look back on a season in which Celtic punched above their weight in the European area to reach the Champions League last 16.
However, he knows it will forever be a battle for Scottish clubs to haul themselves off the ropes.
"The hardest thing, I think, will be trying to have seasons like this one again," he said.
"If we can maintain that, then I don't think it's going to be an unattractive proposition for players to come here.
"If we can't get Champions League football every year then I think it's going to be more difficult until if and when Rangers get back into the SPL, and then you have the rivalry back and that becomes more of an attractive proposition for players."
Celtic face Juventus in the second leg of their last 16 tie a week tomorrow facing an uphill task to turn around a 3-0 deficit.
It has been a heroic effort from Lennon's team to reach this stage of the tournament. The manager believes they have achieved the mark despite rivals in the Scottish game willing the Bhoys to fall flat on their faces.
He said: "There was huge pressure, there was huge negativity going into the games.
"No-one gave us a prayer really, they thought qualification would be difficult – and I did too, because it came so early and our previous attempts at it had not been great – but we seemed to find the right blend, we got the timing right, we got the pre-season right. That put us in good stead for the remainder of the season.
"I can't help what other people think. That happens in every country: AC Milan want Inter Milan to fail, Spurs want Arsenal to fail, Man City want Man United to fail, but it's very engrossing in this country because we seem to dominate the footballing landscape."