That was years ago when they sold them young. FR have cut back on selling planes as the last order ended. When they start selling again the average age of those sold will mean the buyer will want a massive discount.
You really don't do figures that well do you....
Ave Fare - €50 (and rising)
Ave Pax per plane per year 400,000 (80 M Pax / 200 aircraft, its more as ground 80 for 4-5 months )
Ave Profit margin - 12%
(All info available)
So make roughly €3 M per plane per year at a guess.
Given you paid prob €20 M (or less) a plane and even if keep 10 yrs and sell for half then you still quids in.
Holding for 5 yrs means more profit as not spending billions to buy new ones.
And the downside again is where ?