I third this.
Im not really sure what the point being made here is. Silver Lions are earned yes but also spent on repairs, shells, ammunition and anything else. If you have been playing for 6 years, you would indeed have been earning, but to maximize earnings its best to play spesific vehicles. Its also impossible to judge what you have done with all of your SL over 6 years and simply showing your unpurchased vehicles does not really give the whole story.
Its like saying you swam for 6 years in 500 different swimming pools. If you didnt improve your technique or challenge yourself, you cant expect to automatically qualify for the Olympics just because you swam for 6 years.