What's with all the arguing about who is making more new IPs? Sony entrust their big studios to make new IPs while MS doesn't (Evolutuon - DC, Naughty Dog - TLOU, GG - Horizon, Media Molcule- Dreams, Santa Monica - Unannounced new IP). But MS invest in new IPs in different ways like funding 3rd party projects and some smaller AA titles.
Also MS might of bought TROTR exclusivity but Sony also spent money to get Street Fighter exclusive. They invest in 3rd party exclusives to benefit them so in the long run, the money spent on the exclusives will bring them in money (money for being publishers and extra money and bigger install base from the extra consoles sold because of them).
So to answer the OP, MS do not look at the Tomb Raider as throwing money away but to benefit them so it shouldn't affect if they should fund in Phantom Dust or not. MS would of looked at how much PD would sell and how much it would sell for, from that they can work out its budget. The studio needed more money to make the game work so MS pulled the plug. Harsh but a smart move from MS. Not sure if PD will ever be made because I can't see MS wanting to pump more money into restarting the project.
