Then I guess every Nintendo handheld ever is bad hardware by your skewed definition.

I really think that the bolded is The Answer.

I too thought the hardware was great. And, anyone who's played Killzone Mercenary knows that the Vita was more than capable of creating a 'console experience on the go'. When the Vita followed the successful methods of the PSP*, it often (but not always) excelled. I would argue, it also excelled when it put offered solid experiences that were tailored to the Vita itself. Toukiden: Age of Demons and Kiwami come to mind (I know the latter was on the PS4, but it very much feels like a Vita game still), Freedom Wars, Soul Sacrifice & SS:Delta, Gravity Rush, & Tearaway (again, yes, there's a PS4 version, but I very much prefer it on the Vita).

I would agree with Rolstoppable that the hardware was ill-suited to a lot of multi-platform games, but that is one of my qualms with multi-plats - they generally are not built around a specific platform's abilities and limitations. So, if a piece of hardware has fewer buttons than the others? Yeah, its port is likely going to suffer. E.g. I did not miss the lack of an L2/R2 button on any of the games listed above. But Bloodborne on the Vita via remote play? Yes, I very much miss my 2s & 3s and the touchpad is not a sufficient surrogate for me.

All of that said, there are two additional factors I haven't seen brought up here (one of which I'm curious about and the other I'm fairly confident contributed to the Vita's poor performance).

1. I wonder, given how many PSPs were out there (regardless of all of the hackery and pirating), if Sony had implemented an easy/free UMD-digital conversion system (like they did in Japan but without the fee) whether it would have led to a significant increase in PSP owner migrations to the Vita. I know that there would have been a tremendous amount of logistical hurdles, including validation of purchase, memory card space, etc., but, if said kinks could have been resolved, I still wonder if it would have had a worthwhile impact (certainly would have been a point in favor of Sony using micro-SDs...sigh).
2. I knew right from its reveal that calling it the PS Vita was a mistake. Sony had established a trend of numbering relatively utilitarian names for their gaming systems. Having worked far too long in video game retail, all customers understood that the PS2 was 'better' (or at least newer, more powerful, etc.) than the PS1 because it was a higher number. They understood that the PS3 was 'better' than the PS1 and PS2. They even understood that the PSP was just a PlayStation that was portable. That didn't mean that there weren't questions about what was different, etc., but, intuitively, people got it. Going from the Xbox to the Xbox 360 wasn't as clean, but we got there. Going from the 360 to the Xbox One was...less so. Still, at least numbers were involved, regardless of how counter-intuitive many found the naming schemes to be. Going from the PSP to PS Vita created a tremendous amount of customer confusion. "Is it an add on?" "Is this like an offshoot until the PSP2?" "Okay, so it's the new one? So it doesn't play PSP games right?" "Why would they pick Vita?" etc. I realize all of this sounds pedantic, and I know that I'm pulling from anecdotal evidence, but, in my experience, the name was a tremendous source of confusion for the first couple of years (you know, right up to the point when Sony, more or less, pulled 1st party support). And I can confirm that, in speaking with others working in video game retail, this confusion was geographically widespread and consistent.

*This was the trend Sony noted during the PSP in which unique, PSP-specific entries into established franchises proved to be highly successful (commercially, if nothing else). Examples would include GoWs: Chains of Olympus & Ghost of Sparta, FF7:CC, Resistance: Retribution, Metal Gear Solids Portable Ops & Peacewalker, GTA: Liberty & Vice City Stories, etc.

TLDR: Sony failed the Vita - Leynos

“No” games. Or in any case, no games of note, there were no system sellers. I only have it because I wanted to play Uncharted, which was an okay game, but I have no idea what else I’d want to play. On top of that it was expensive, required equally expensive memory cards and was barely marketed.

The Vita was fantastic. I picked up the Assassin's Creed bundle for $188 in 2012 I believe. I didn't even mind paying extra for menory cards. Probably didn't offer much for those not interested in Japanese games though.

I never expected it to be current gen quality on the go but it was close enough.

Cause the curse of the non Nintendo portable killed it.

The mistakes with the price point, memory cards, and game line-up have all been mentioned already, but I think what really made them fatal errors was the system coming out right around the time the 3DS was really hitting its stride. Had the 3DS had the same situation as the Wii U where it took a year before the system had any games worth buying, then it might have given Sony the time they needed to turn things around with the Vita. Instead, well, they pretty much ended up in the same situation that Microsoft did with the Xbox One the following year.

I must have missed when Vita got Skyrim, Crash N. Sane Trilogy, Crash Nitro Fuel, DOOM, Wolfenstein, Dragon Quest 11, Snake Pass, etc. I get a lot of those games came out after the Vita was relevant, and there are a number of titles which were on the Vita but weren't good ports (like for example Borderlands 2), but the point still stands. It's a little silly to act like Vita had some really good library comparable to the Switch, then to explain later on that it had a lack of killer first party titles. Ok ... then it didn't have a comparable library? Even if we're just talking third party, there's a number of reasons why the third party on the Switch is more attractive than that on the Vita. Even putting aside major third party exclusives, the Switch's third party games are just generally bigger and more successful. Especially because they emulate consoles much more closely (which is important for games like Borderlands). Also, good first party titles kind of act as a gateway for consoles, especially handhelds where bigger publishers (especially western ones) and bigger games from said publishers are not coming out right out of the gate. 

Like sure, you have a lot of the same genres that are popular on both systems, and you even have a lot of junk on the Switch, but that doesn't particularly matter because it doesn't answer what games are on the system, which is more important than just a broad generalization of what kind of games are on it.. And coincidentally a lot of the best selling third party games are in genres that the Vita didn't cover or didn't cover well. So in conclusion, it's really not a jump in logic to say that the Vita has a bad library, but the Switch doesn't. There are a number of very valid reasons that could lead to such a conclusion. 

There's not much else I can add that's not been mentioned many times already but doing the proprietary memory card thing is something you'd expect from Nintendo, not Sony; although given the fact that Sony has gone down that route several times previously with the PSP and PSP Go, we expected them to learn. Especially with the rising popularity of the near universal microSD cards at the time, a format the 3DS/2DS handheld family and Switch uses alongside the smartphones and tablets.

I guess you could say it had no life, that is was deat on arrival...

I'll see myself out.

Sony should consider making PS Vita titles available through PS Now.

OT: Price, lack of compelling software, and the mobile market.