1. You obvioulsy don't understand the difference between a JRPG and a Western RPG... Oblivion and Fable are not the same type of games as Final Fantasy and Dragon Quest... they might both be "RPGs" but they're barely the same Genre. You might as well compare Halo to Tekken.
2. Microsoft didn't make Oblivion and they didn't make Fable either. Why are you complaining about Microsoft when it was 3rd parties who made those games. Sure Lionhead (Fables development studio) is NOW owned by Microsoft, but they weren't when Fable was made. You haven't even seen a Microsoft brand RPG yet.
3. You say they're losing the RPG crowd... to whom exactly? They're certainly not losing it to the PS3, considering the only RPGs on that console are MUA, Enchanted Arms and Oblivion, All are which availble for the 360 as well and we already know how you feel about those games. They're probably not really losing it to the Wii either considering Zelda is their only RPG and really many would argue that it's more of an adventure game then an RPG.. it's certainly not a traditional JRPG that you seem to be so fond of.
4. If you haven't realized Blue Dragon will be released in the USA soon (it's already been released in japan) This is a title actually made by Microsoft and wouldn't you know it's made by the same guy who used to make Final Fantasy games... it's also an extension of the Chrono Trigger world. It was met with great praise and many JRPG fans are heralding it as one of the best RPGs of that style to come out in years. It sounds to me that MS knows the RPG market better then you think. After that they're releasing Lost Odyssey, another JRPG, you should look it up. Some Western RPGs like Mass Effect are arriving soon as well.
You should really do your research before you start a bitch fest, because complaining about things you're completely uninformed about just makes you look like an idiot.
In the mean time if you really want to play some JRPGs buy a DS and pickup the FF III an IV re-releases.