to make something exclusive you need yo pay more than just development cost,  the funds need to cover the loss of sales from the excluded platforms as well as advertising agressively to increase single playform sales. 

would take a hell of a lot more than 200mill.

as things are though,  with many xbox fans snubbing destiny because they see bungie as being traitors,  and the obvioud leaning towards playstation,  it may as well be a playstation excludive as far as success and sales go,  bungie just benefit from the sales of other platforms,  ensuring the game doesnt die off. 

No I mean they should've got to Bungie before Activision did.

Yeah it's just that Sony really needs to start getting exclusive killer apps soon... same with Xbox One. Destiny is on the PS3/Xbox 360 as well.... PS4 needs real system sellers soon.

I don't think Bungie broke from Microsoft so that they could go Sony exclusive.  I think their overall goal was to simply be a multi-plat dev, even if they did do some timed exclusive stuff with one company or another.  Even if Sony had the money, it just didn't seem like Bungie was trending that way.  More reasonably, they saw how their IP did on an exclusive platform, and were seeing the possible dollar signs, if they were releasing on double the hardware or more.

Gain control over the IP and going multiplat is a great financial deal for the developers.

Bungie did it to make more money.