It really isn't. The first years dominate the value and later years are worth nothing due to inflation. Google a calculator and use a reasonable discount rate and I suspect you will find that todays value for an infinite perpetuity is a lot less than your intuition might guess. It always surprises me.
It costs me $10M to run something every year, it now costs me $4M to run something every year. I have $6M in my pocket every year now in perpetuity. Compound that annually with the assumption that I maintain or increase top line revenues and thats pure extra profit.
Note - I admit, all of this ignores two key things (a) we dont know the engineers salaries who built this and (b) we dont know the ongoing maintenance costs.