The further in the future profits are, the less they are worth today. As in getting $1000 today is better, then getting a promise of being paid $1000 in a decade. After all if you got the $1000 today you could have invested it and got a return on it. So lets say you know you can get a return of a rate of 5%. The $1000 today invested over a decade would be $1000 * 1.0510 = $1628.89 in a decade. You can also use it the other way around, to estimate what the $1000 is worth in the future. As in X * 1.0510 = $1000 -> X =$613.91 That rate of return is called the discount rate.
The issue with getting money in 50 years is that it ends up being nearly nothing today. So it is just a horrible idea.







Yes we are. In a mortgage the bank gives you the money today, for the promise of payments in the future. So for a bank far out payments are nearly worthless today. So they will not give you better conditions for a 50year mortgage compared to a 25year one.