For my formative years as a young person and a gamer, I was huge into portable gaming. I was a Gameboy fanatic since '98 and I played the crap out of that thing. I also played console games and some PC games, but the portable platforms were my bread and butter.
My preferred console was always the Playstation and the PS2, so when the PSP was first released back in 2004 I was ecstatic to give it a shot.
Of course, it was absurdly expensive and not something I could convince my parents to buy me. So I had to wait for a couple incarnations of it, but I was still a fan from jump.
As the years went on, I made heavy use of my PSP.
More than just something to play games on, it was also a basic internet browser, an mp3 player, a video player, and a photo gallery viewer. It was my entertainment hub on-the-go.
Games released for the PSP were mostly hit or miss. The fact that there wasn't a second joystick made it hard for certain games to operate well. It also limited the things that could be done for types of games. There was potential for the device, because it could handle graphics that other portables couldn't, but it got under-utilized.
I eventually graduated to the PSP Go, which was run entirely on internal memory storage. No more UMDs that everyone was so fond of complaining about. It also meant no more physical copies, and I'm personally a fan of having a physical copy around to hang onto.
The incoming games slowed down significantly. The PSP had been recieving a lot of negative press and the fact that it had gone through two or three new versions still without a second joystick was another nail in its coffin.
Mobile gaming was slowly gaining traction as the PSP started losing it, and that could account for the diminshed sales of portable games. People became more interested in games they din't need additional devices for. Games for phones were becoming far more popular with the layman. Sony didn't keep up with the demands of its consumers.
Only very late into the dwindling of the PSP did they finally address the second joystick issue with the PS Vita. The Vita has a touchscreen back and two joysticks, only a full decade after people began asking for it. So yeah, it's nice to have, but way too late to make much of a difference.