You suspect. We don't actually know.
The fact that third parties, and Sony itself, are avoiding the platform is more than a proof. Remember, the first Sony platform to not have a top-tier support from Konami, Capcom, Square Enix and Namco Bandai, third parties that always supported Sony.
And yet the 2013 lineup seems to be comparable to 3DS in quantity.
When one 3DS game -Dragon Quest VII- will sell 5 times the entire 2013 Vita line-up, does it really matter? You have also to consider that many 3DS games will keep selling in 2013 even though they've been released in 2012; Run for Money, Inazuma Eleven, Magician's Quest, etc. won't disappear so easily from the chart.
Also: I'm not really sure whether line-up are comparable in quantitative terms. And if so, how many Vita games are exclusives?
It's much closer in capabilities to the consoles, making it the wiser choice for multi-plats. Do we know what the attach rate is for the 3DS and the Vita? It might have a smaller base buying more games, who knows?
Who cares if people buy more games, when software sales are abysmal? Did you really have a look at the chart this week? Look how many Vita games in the Top30, and how many 3DS games.
Again, why develop for the 3DS if the return on investment for iOS devices is much higher? Yet, people do.
Returns are much higher? I'm doubtful Square Enix will earn more from FFIV on iOS than from DQVII on 3DS, given the price at which they're sold.
You say that as if the 2013 lineups were miles apart. They aren't. You're not talking about the reality of now, you're talking about how you think it should be.
I repeat myself: software houses are clearly avoiding Vita. The situation speaks for itself. Some multi here and there, and ultraniche exclusive games don't mean something different. This support is abysmal even compared to what GC got. I mean, GC.
Mobile gaming pre-iOS and mobile gaming post-iOS are utterly different ballgames.
You seem to think that all 3rd party development for the Vita has ceased. It hasn't. You seem to think it should cease. It won't. You're not looking past the larger userbase of the 3DS to see that there are other factors at play.
You mentioned myriad of factors to develop for Vita instead for 3DS; you barley cited 3 of them, and none of them makes sense if we talk about business decisions. Of course when I say that software houses don't support Vita doesn't mean that they don't develop games at all; they just put the minimum effort. Neither Sony doesn't believe in the platform anymore.