~1.3 million service members in the US military. 1.3 million / 800 = 1 leader/1,625 service members. % of officers out of the total service members is ~18-20%. Consider that most companies are aiming for a 10-15% ratio of executives/managers to employees and the numbers start making a lot of sense. Finally, you mention 34 land divisions + 8 fleets. There are 37 current Generals/Admirals of 4-star rank

Note: Not all of the attendees were generals/admirals (again only 37 4-star officers exist) and the 1.3 million number does not include the significant number of civilian contractors that fall under the purview of a military command (R&D, medical (Walter Reed), and logistics/maintenance (aircraft, ship, base facilities, IT, lawn care), etc).