Why would rockstar not also pay senior staff obscene amounts of money?
Yes, staff size fluctuate, this also applies to bungie. You don't think they started out with 500 people right? They had around 150 when they made Reach. Halo Reach came out after ODST btw.
I'm not saying Destiny is a cheap game. But there is a LARGE gap between 200 (we don't really know if this is what has been spend on Destiny though) and 500 million. And no, that gap ain't gonna be filled by the PR budget.
CoD going through 500 million in 5 years ( assuming that's the number ). Also means the production and big marketing campaigns for 5 games. Bungie aren't going to make 5 games in a 10 year span.
In end both you and I are pulling numbers out our asses. Neither us know the exact budgets any of these games have. I'm simply trying to look at this logically. And I just don't see how Bungie could possible spend 2 times the amount of money making Destiny, as Rockstar did with more people working on GTA5, over roughly as long of a time period. Nor do I think that Activision would being willing to bet such a large amount of money on a single new IP game. And that won't change no matter how much we speculate on the fee's of a few voice actors, musician, senior staff wages or unknown budgets of games and marketing campaigns.