First, as I said above, I earn 3,000 Zen per month in total: 500 from my Stipend and 2,500 more from playing. That's enough for me to buy a new C-Store ship each month and Keys - though I don't buy Keys as I have no real interest in Lockboxes.
Second, as I also said above, Lockboxes make the company money. That money pays for development. We have Fleetbases because Lockboxes paid to develop them. We'll have a new Zone and Missions with Season 7 because Lockboxes paid to develop them. Lockboxes make money, which pays for everything else.
Third, anyone spending $400.00-$500.00 to get a Lockbox ship is an major idiot who should be sterilized so-as to not pass on their lunacy.