http://www.faforever.com/faf/unitsDB/un ... 04,UAB2304
Just in case people forgot the numbers, you should check the costs of each type of unit. Maybe we won't see that lie that sam are NOT effective enough. 1:3 mass wise, 1:13 energy wise and probably the most important when it comes to the timeframe where snipes become real dangers , so lategame, 1:10 build time wise , 1:10 ....
IF with those numbers you can't figure out that against proper defense (don't be "unwise" and pack all your sams next to you ), sniping is a huge gamble and investment, then well I'm not sure how to convince you any further.
Add to that , that for a fraction of the cost of a strat, you can get a FEW, a FEW t2 shields that will save you from a hypothetical mispositioning of your SAMs, and give them time to snipe enough bombers so that you don't get killed.
Most of the time when I watch games where strat sniping worked, either there was no adequate defense (shields + sams WELL positioned) or one team simply had complete and SUPER MASSIVE dominance in terms of ASF.