If music industry is anything to go by - out of £20 for a game, about £5 goes to retail chain, £10 to publisher and probably less than £2 to developers, if they actually have any syndication in contract, otherwise there is some flat fee upon completion.
And with that in mind - unless you are your own stable, track, jockey and horse, like Crytek - whether you create multimillion selling game does not make any big difference to the developer except doing exceptionally well creates higher demand for them to maintain, update and patch the product indefinitely. So in short between delivering average PC game to publisher and delivering average console game to publisher, the studio is better off to go down console route. Because:
a) console games are easier to make (no hardware variability, sdk out of the box, strict set of settings, etc)
b) console games are less demanding in aftercare (no one's going to petition you for walljump and double kick'o'stab with a mage staff for next patch of your average Halo clone)
c) console market is numpt - even if you make a game that plays like wolfstein 3d and looks like "rage guy" meme it will sell like hell, even if only because if every game store takes one and every Blockbusters and GameStop and GameCrazy outfit buys 5 disks with your cack you are already selling close to half a million copies world wide. Let's face it, you could buy unreal engine license, model a turd, paint that turd gold, put helmet on it, and as long as it shoots something, bleeds profusely and has helpful autoaim when used with 4 button controller - you are going to make your publisher happy as if you... ahem... turned turd into gold?
d) console games allow for quick and sloppy coding - it's not like two days after release you are going to have wallhacks and god mode server cheats if you don't revise your code and go through months of beta testing. The chances of most of your console game bugs seeing daylight is slimmer than remote chance anyone would buy the game if it was released on PC. Which partially why "porting" process takes a year sometimes.