PSP didn't sell all that many games, it hardly constitutes as a success in my book. 

Piracy hurt it a lot, among other things. 

It sold more software than 3DS, N64, and GCN, and that's not counting digital. I guess none of those platforms are a success?

The 3DS outsold PSP's software by 30+ million units with 13 million less units sold. That's not even accounting for the fact that Capcom confirmed that at least one of the MH games on PSP is overtracked on VGChartz by almost 2 million. Beyond that, the GBA sold as much as the PSP but sold 80+ million more software sales. Besides that, the Gamecube has an attach rate of 10:1 compared to the PSP's 3.75:1

That being said, the PSP was most definitely a success, just kind of moderate. 

The GC and N64 are success stories now? 

And digital sales for 3DS will be a lot higher than PSP, not to mention the fact that it's not done selling yet. 

PSP has an atrocious tie ratio for a system that sold 80M units. 

http://www.vgchartz.com/analysis/platform_totals/Software/Global/

PSP beats 3DS by around 9m right now. Probably won't be the case for much longer, but its current.

3DS may as well be done selling. That said, I don't doubt that digitally it's a much closer and in 3DS's favor, I feel it's only fitting to point out that the PSP wasn't even close to a failure. The only people who think that are the ones too blinded by the brilliance of the DS's sales numbers to recognize that not every console moves 150m+ units with over 800m software sales. If you want to get into it, though, we can point out the PS2's software sales and argue the DS was a failure for to rampant R4 piracy.

https://www.nintendo.co.jp/ir/en/finance/hard_soft/index.html

I defer to Nintendo's official numbers, then. Doesn't change the fact that PSP had more software sold than N64, nor does it mean the PSP wasn't a success.

Of course, which is what I originally agreed with. However, that level of argumentation is a slipery slope and I think you can admit it's not nuanced either. The N64 had 6.83 software sold per console, the Gamecube had about 10(it's total software was near N64 levels despite selling 12 million less), and the PSP sold 80 million console units with about 3.75 software sold per console. It wasn't a resounding success from a software perspective, although it was a moderate success as a whole especially from a hardware standpoint. 

Right, as far as tie-in is concerned, PSP didn't do so well. However, it should be noted that there are many uncounted digital PSP software sales thanks to both the PSPgo and Vita. At the same time, arguing only tie-in is a slippery slope, too. Yes, Wii U has one of the highest attach-rates in console history... But it's also Nintendo's biggest mainstream failure.

I don't think id count Vita sales of PSP tites since you're making a point regarding PSP's success. That would be like counting Virtual Console sales for NES. But I agree with you. For what it's worth, I wish that Sony would just do a 3rd PSP. I don't think it's far how PSP is looked back on. At the same time, though, it's really a testimant to how poor it did in comparison to the DS that PSP had sooooo many iterations and sold 80 million. I think that's a big reason why it got  there, because Sony would just not give up on making it the most trending thing imaginable. DS had a lot of iterations but that was a natural extension of it's sales