I dont think WE even have 20,000 tanks . I dont think Russia has 20,000 tanks lol . Unless you are producing WW2 style technology tanks , you could produce that number…………………..in several years . The modern tank is not a simple , or easy piece of equipment to produce . Here is another thing about tanks . Tanks need a crew , and that is what ? 4-5 people , but its not just the tank , for every one tank , you need not a small number of support to keep it going . You have to have X number of fuel trucks , X number of other support vehicles and logistics . That takes man power . What is the Saudi population ? Last I knew , imported foreign labor outnumbered the population of Saudi citizens already . Then how many infantry could be called up ? Its a struggle for us to come up with , and sustain large numbers of troops . I would question the numbers also .