Steamdeck sold what, 3-4 million copies until now maybe? Yes, I see PS Portal selling more than this.
Specially once people hack it to put there emulators, and or when Sony would update it to officially include there PS cloud gaming, their PS1/PS2/PSP classics and maybe even their mobile phone games too.
But Sony won't make games specifically for this. It's a remote play device, maximum once they release the PS cloud gaming client and some games for Android they could include them here too because it's an Android device. As of now, the goal of the device is to increase player engagement (like daily or weekly gameplay hours) of the PS5 games via remote play.
I think it may even outsell the Vita specially if it gets some review to add an oled screen, wifi6 and the tech of the company they just bought to reduce the lag. But not sure if they'll spend a lot of work on firmware updates, hardware revisions or updating remote play even if very successful. They may even just wait to impleent all the improvements in hte next gen: PS Portal 2 for PS6.
Yes. Sony considered a success recent releases such as PSVR2, DualSense Edge and other accesories. We didn't get repors from them getting sold out in stores or preorders, and we got them with PS Portal.