But it had already been announced to PSP. It went to Vita mostly because it had to be delayed and by the time it would be released, Banco realized it wouldn't do releasing only for PSP in late 2013.
Because this is the incorrect interpretation, that is why it is ridiculous. They released Toukiden on Vita because they knew the profile of the average Vita owner through the researches that have been made, and knew there were many Vita owners that were frustrated for the lack of Monster Hunter, so that they could fill the void if they had a good game.
It was more like Sony felt pressured to give some kind of support to Vita when they realized they wouldn't be getting a lot of 3rd party support. Because most of their IPs would not help that much, they tried to gamble in a genre they knew their customers were interested in, and other projects that didn't take a lot of resources, like Tearaway, Killzone Mercenary and Oreshika. That support dried up quickly, though, as they decided to focus on PS4 and rebrand Vita as a PS4 accessory.
Your list consists of many Square series. Suikoden was released before FFVII, Megaten had a presence on Saturn. Some series went to the most successful console and some avoided Saturn because by the time they were made, Sega had already announced or even launched Dreamcast. It is not just a "follow the leader" thing, there are reasons, and the reasons why most didn't stick with N64 are obviously technological. Even the smallest PS and Saturn RPGs wouldn't fit in on cartridge.
Your argument is based on being "wise after the event" for hunting games not going to 3DS. Apart from Toukiden, the games you mention were either planned for Playstation platforms or are developed by Sony. Even so, none of the games were announced after Monster Hunter 4 was released on 3DS, so it is not a situation like FFVII, were many of games you mention are 1998, 1999, or even 2000, so that they were either planned after FFVII success or were at early stages of development and were already burned by Nintendo 64 being on cartridges, making it almost impossible to develop compelling RPGs for it. The fact that no new hunting games were announced for Vita after MH4 release apart for the extended versions makes your point moot. How could they know Monster Hunter 4 would not have a worrying decline on 3DS before knowing how it had performed?
I take issue of people making wild claims to support their biased arguments. The objective of claiming that Sony obviously moneyhatted games with no proof is to support the argument that every game should be released on 3DS, and when they aren't is that something "wrong" happened. But being moneyhatted, stubborn, greedy and liking to suffer are not the only reasons why publishers make games for other platforms. It is not through the insistence of four or five members, that are constantly on MC threads, in repeating this mantra at every opportunity that it will become true.