I don't really follow.
Do you mean previous JRPGs that have been released? As in the ones that are on the shelf right now? I highly doubtr it. You'll probably see a small amount of people who are going to the store and buying FFXIII and 'that second RPG they were waiting to get'. But there's going to be just as many people looking to buy another JRPG such as Demon Souls, Tales of Vesperia or Pokemon Gold/Silver as their secondary purchase as there are those who will pick up Mass Effect 2, Dragon Age or the latest expansion of WoW.
In the end, like anything released in the 'west', what will improve the sales of JRPGs is better marketing, more hype for new titles and more availability of the product. And JRPGs have been lacking in all three. Aside from a handful of titles this gen (FFXIII, Mario & Luigi: Bowsers Inside Story, Pokemon), JRPGs have been pretty much thrown to the wolves and expected to sell as well as they can given the circumstances. And considering the marketing budgets and amount of stock most JRPGs get...that's not very good.
Six upcoming games you should look into:
