OK, say for an average case, you are 40 and live another 40 year

The accumulated appreciated premium is

700*(1+i)^40 + 700*(1+i)^39+ ... + 700, i is the return rate. To get 400k accumulated value, i has to be something like 9.4%.

Now, if out of the 900, the company keeps 200 for management fee... They will need even higher return to cover the obligations.