Do you know that they own the IP's to those games? Microsoft published Mass Effect...

 Uh...yes. Duh, up to a couple of months ago Bungie was owned by MS. meaning MS had alot more to gain keeping halo exclusive, as already explained Insomniac isn't owned by Sony, if they were then obviously they would exist to help sony, and sony would be better benefited with more exclusives then they would with additional sales on compititor's platforms. One other issue though is publishing and size of development groups,multiplat games require alot more resources and I don't believe any of these publish there games, they allow sony and microsoft to do that, and since theyown the platform and are willing to compensate the developer handsomely for it then I guess the developer doesn't mind they have an easier time focusing their energy on one platform. While bigger companies that do publish there work are looking for the most bang for their buck. So if Insomniac wanted to expand there business I guess they'd have to start developing ties with other companies, and it does seem eaiser to stick with Sony.

The clear implication is no multi-platform titles in foreseeable future but not ruled out either.

What I could imagine them trying (if they do want to try cross platform) is something for the Wii. Given how much their current engine has been designed from ground up for PS3 I would imagine going for 360 (while obvious) would be expensive for them and demand a big staff hike. A lower cost, lower risk Wii game (something fun like R&c say rather than RFOM FPS) would make sense for them and I bet they'd have some fun with the Wii controls.

Are sucker punch owned by Sony?

OT: There is no hint that they will go multiplatform. They can act as though they are first party, and get sony to do all the advertising, and the co-operate with other Sony studios, at the end of Ratchet in the credits they thank other sony studios for helping them. They get the first access to dev tools. If they were not so close to Sony they would not have been able to make a game every year, which is amazing, considering the quality of each game.

 It's a common thing for publishers to own the rights to the games they publish, although this isn't always the case. In terms of Mass Effect, I believe that EA currently has the rights to the franchise as they accuired Bioware recently. Rare also retained the rights to their IP's.

Ratchet & Clank and Resistance are franchises owned by SCE though:

 Source

If they were really going to jump ship, wouldn't they have done it already, instead of waiting until the PS3 is about to reach 10mil sold?

Also the author really infers a lot from very short quotes. Why not give us the raw interview somewhere if it has so many scoops?

If Insomniac releases future R&C titles on other systems I will lose respect for them.

Other titles I wouldn't mind but not R&C same goes for Resistance.

 First off, I 100% we will never see Ratchet & Clank or Resistance on the 360 or Wii or see Insomniac release something for another platform within the next two years.  Just setting things straight in case people misunderstand me.

What this article does hint at is that Insomniac does see the advantage and they are completely open to it when they have the manpower.  What that means is they don't have it at the moment because they are already committed to working on other projects.  As they finish projects, they will have the bandwidth to make different games if they see fit.

Does this confirm that they will make one of their games multiplatform?  Of course not.

Does this confirm that they will make any game for any other platform?  No.

Does this open the possibility that they will make a game for another platform?  Yes.