Because Siren is not Silent Hill, not even close.

Dont think Silent Hills will be cheap (since Konami dont even know a lot of IPs, they will probably want a lot of money) and Konami will probably want revenue sharing which is a bad deal considering it is not guaranteed to sell.

I don't think it's impossible. Konami will want all the successes they can get right now, plus they might see this as an opportunity to buy back some of that good will that they lost in the Kojima debacle, if they manage to patch things up with him. On the oher side, Kojima has been wanting to make another Silent Hill, or at least a good horror game for some time now. What better way to accomplish that, than to pick up what he already started with P.T.?

Maybe he loves Silent Hill? The first 3 games had a daring vision and were superbly executed despite the hardware limitations, they are pure examples of video games as high art, they were never just "horror games" in my opinion until the creative team left after the original trilogy, and I think Kojima understands that and wants to reimagine the IP in a faithful manner, as someone who has always wanted to push the medium further, I think Silent Hill is a perfect fit for him (regardless if we think he's successful at achieving his goals or not).

Moreover, Konami isn't interested in making anymore SH games and they'd probably make more money by selling the IP to SONY or Kojima. 

Or, you know, make something original for a change.

Well that would make the whole fight between them a lot more curious.

No, just no lol. C'mon, we all know what's in a name. We know how much things sell based on brand power alone. Heck, if they changed the name of PlayStation to GameStation I bet it wouldn't sell as much anymore. Just saying.

It has to be a new Silent Hill with the same concepts. It's just too incredible of a franchise to just create something new now. Plus, the fans of SH are a very dedicated bunch. They deserve another one if only for it to be the LAST one.

This I agree, but for Kojima to be involved... MAKE.IT.HAPPEN.

Yes there's power behind a name but I think that Kojima's name alone would be enough to boost a new horror IP well over what Silent Hill ever achieved in terms of sales. If Kojima was able to sell a post-apocalyptic postman simulator IP on his name alone selling a new horror IP should be quite easy.

not really, look at metal gear survive, the backlash partially for using metal gear name when it's not a metal gear game and partially due to support from fans from Mr Kojima, if Konami, used a different name, ie, zombie survive, or surviving dimenions or some thing like, the sales would be significantly better