tc wont give you shit. it is supposed to, but it simply doesnt pay. due to the eploiting griefer gangs, that will take the city over just to interupt the income growth.
you are not missing that much. what you are missing is 1) loosing moneys trying to secure the city, naively thinking it will pay back 2) cheap reason for occasional pk.
no caps.
now the best way to get caps is sell to players. there is tons of -somehow- easily obtainable stuff that players will buy in large quantities, and they will pay more than merchants. .223, 7.62, MFC, BA, DKS, LSW, Plasma weapontry, drugs. all that sells great.
you can actually make a lot of moneys at traders, too. selling the excess stuff. good barter character (high carry weight, good OD, decent barter, few-weeks-old raider) gets 50k on average per a barter run.
also, raising barter above 150 (about 200 tops) gets you 75% base price even on unwanted items. so, if you see HUGE caps deposits, you can make that call and sell all the shit there with not so big loses.
if nothing like that suits ya... farm the caps. im just mentioning that is possible, though its long, annoying and boring thing to do.
to make it complete, drink A LOT of nuka cola.