Ok, so first I would like to point out that this is a very tough period for Sony financially. They will soon be releasing Vita, which is expected to sell at a loss on hardware for 3 years. This is particularly bad for handhelds - extra controllers on home consoles are a great source of income). They are also no doubt spending a lot of RnD money finishing the PS4, which shall release shortly afterafter Vita, and which will also likely be sold at a loss for the first 2+ years.
What this means, is that Sony have to be very careful about what developers they buy, and what new studios they open.
With the exception of those made by Nintendo or Square-Enix, JRPG's do not generally sell particularly well. This is doubly true this generation, the majority of new JRPG franchises have underperformed. Almost all the exceptions to this are on the DS. Look for example at all the money Microsoft poured into moneyhatting some (timed) exclusive JRPGs - total waste of money.
As for WRPGs, these also have a great danger of underperforming. Many do quite well, but others do not, and they can be quite expensive to make.
Sony have by far the largest 1st party, but they are squandering its potential. They need to cut unprofitable studios, and focus on games that they know there is an audience for, and most importantly, they need to win back third party support.
Also, platformers are much more popular as a genre than you appear to believe.
