You forgot a very large detail about the commission structure. The commission percentages given apply ONLY on the policies you sell directly yourself. Bearing in mind that in 2015, the average new policies sold per rep PER YEAR was 2.54, and only 2.28 in 2014.
On policies sold by your downlines, you only receive an "override" which is the difference between their commission % and your own. Typically that works out to a 10%-15% commission rate. Therefore your downlines need to sell 2 1/2 policies to generate the commissions selling one policy yourself would generate.
Again, bearing in mind the policies sold per year averages above, each new downline you add will only produce the commissions of one policy sale PER YEAR as far as your pocket is concerned.
Typically, the commissions paid to a rep for each policy they sell themselves is in the $100-$200 range. If a downline made the sale, you'll receive a $40-$80 override commission.
Now lets look at the real numbers, per Primerica's annual reports. You may have to convince 30 to 40 friends to attend an opportunity meeting, in order to convince 8 of them to join (pay their IBA fee). Of these 8 recruits, only 2 may remain for training and/or pass their exam, and only then can they start selling and producing an override for you.
And within a year, 1 of them may quit, and they other may be a "dud". The average Primerican rep has only recruited 2 1/2 people at best the last several years, so even the above scenario is based on a "best case".
And lets not forget, all the while your waiting for these commissions to come in, you're spending money on gas to get to and from their twice weekly office meetings, and to and from any client appointments, your monthly POL fees, any business cards or brochures you have to pay for, special seminar fees, etc etc etc.