I´m talking about the evident sales trends that show steep decline. Your list is actually a confirmation since DQBuilders is almost a year old and most of the list that are from your point of view supposed to be good, actually show clearly declining software sales compared to previous entries. PS4 software sales in Japan surely aren´t a barometer of success, my point is, that the gap between those two is closing, one shows a mildly positive trend, while the other is in the negative (PSV), starting from an already at best ok level. A comparison of the Top 10 selling games this year on PSV and PS4 is also very telling, with PS4 ending the year on top of PSV. But more importantly, just take a look at the actual software sales performance in the past months. It also doesn´t help that World of Final Fantasy looks like to be a flop in Japan (WoFF PSV: ~50k first week), that the PS4 version performs even worse isn´t exactly encouraging either, the same story with the new Sword Art Online, another game with a notable decline compared to past entries.

You are kidding me with this post right?

Sony have, since TGS 2014, tried to shift users over from Vita to PS4.  It's evident through things like their presentation, where they announced Senran Kagura Estival Versus & Ys VIII as PS4 games, not even mentioning the Vita version in their trailers.  Like the advertising for Dragon Quest Builders; Toukiden 2 etc. that was solely focused around PS4 and didn't even mention the Vita version exists.

And after all that, for the past 2 years, Vita versions of these games are still outselling the PS4 versions.  Even a horrendous port like SAO: Hollow Realization looks to have handily outsold the PS4 version, despite there not even being footage of the game pre-release and the director going on record to say "we haven't been able to get the Vita version's framerate up to scratch".

Of course sales are declining with all of this taking place.  And yet the Vita versions of these games are more than holding their own.  They'll continue to decline over the next 2 years too, but that doesn't mean these games are going to stop coming to the console.  Because too big a proportion of their domestic userbase comes from the Vita.  What's the alternative?  PS4 exclusive?  Way to crater your franchise.  PS4/Switch?  It's not even out yet and some of these franchises have a poor track record on Nintendo hardware (Atelier Rorona 3DS says hi).

So yeah.  I still wholeheartedly disagree with the "software sales aren't at a sustaintable level anymore" part of your post because that's just nonsense.  I guess the proof will be in the pudding and we'll see how much longer Vita keeps getting these multi-plats in Japan.  I'm betting we'll see support well through holiday 2017 though, which doesn't indicate to me that software sales aren't sustainable.

This... Vita is Still alive just because jrpgs in Japan... Outside there is already dead. I have mine, but even tho I try to keep using it, gets me borde fast. There are very few good games, and the good ones are already on ps3 or 4, so no real battle here.

Play Valkyria Chronicles 2, it is psp game but really good.

The painting is on the wall, software sales have never been great on PSV and it saw a steep decline even starting from such a modest level. How exactly do you expect good software sales going forward when even PSV hardware sales reached sub 9k units per week levels now? But it´s not just hardware, as we have seen according low software sales at the same time as well. Even a well marketed World of Final Fantasy looks to have barely sold 50k units first week on PSV.

About Atelier, it´s not like recent YSO predictions look very promising, they have the next PSV entry at sub 25k. The Rorona comparison is also nonsensical, that´s like comparing FF tactics to the main series, completely different games besides lose story connections.