Porting takes work, work takes time and money, time and money takes incentive. Every dev encounters problems porting anything to Vita that can't be brute forced to the point of emulation, and some persevere even at cost to themselves (Rain Games with Teslagrad for example, Oddworld for another), others give up and Sony's stepped in before if they have a reason to... they don't have much reason to anymore. I'll be glad to blame Roll 7 too, but just remember in your fallacious argument, that OlliOlli was developed on PC and primed for Steam like any other game would be, but came to Vita first (and probably at all) due entirely to financial incentive and business arrangements.
I didn't make up anything. Sony has always encouraged Vita versions from devs, crossbuy and PS+ support with everything from lowering barriers to development (ex: dev kits, Unity fees), actively pursuing kickstarters in the process and making absolutely certain they come (ie: Hyper Light Drifter) to the Vita platform, and incentivizing ports by agreeing to push a title more with blow/show/store visibility if they also do a Vita version (normal business), and also providing financial incentive for crossbuy and/or PS+ (agreements that are to remain undisclosed, as has been stated by numerous devs when asked how much money they get from PS+, obviously to keep the going wholesale rates negotiable), to flat out paying for port development or developing ports themselves.
This isn't some dark industry secret, it's a touted working relationship and marketing image that Playstation <3 indies, and go out of their way to get games on their systems with everything from #JRPGonVita to #buildingthelist. After Sony stopped their own 1st party support on Vita, they began phasing out the need to even maintain an illusion, it just takes years for them to bow slowly without incurring the maximum amount of consumer confidence backlash and press vulture fuel being thrown on the fire. It takes a confluence of wavering parent company support for 3rd parties, a rise in stature for both a small publisher who handles hot properties like Hotline Miami, and a small indie dev getting a taste of money and clout... to walk away from putting time, work or money in. Sony won't make moves anymore unless it's "oh shit, we better port Banner Saga for these devs because 9000 people on the PS Blog are freaking out and KindaFunnyGames picked up the story, so it's embarrassing and damages our consumer confidence for people to know we only give a shit about the current console that's netting almost-mandatory PS+ subscriptions by the tens of millions"
When you own around 300 Vita games and have spent close to 10k on this platform, and still keeps gladly throwing money at every decent release, you can tell me about not being positive enough and act like you've got one up on me. I'm sure it's fun to be either an apologist or an astroturfer, but you can come off it when you're talking to me.
If Oddworld, Arrowhead and Mike Bithell can get games like New N Tasty, Helldivers and Volume running on this thing, Not a Hero is inexcusable. The only answer is the dev can't or won't hang, the pub can't or won't hang enough to find someone who can, and the parent company can't or won't hang for them.