This debate will go on forever!
The "hybrid-ness" comes from purpose, not physical functionality. Future mobile devices will be hybrid too. The SteamDeck is pretty much a hybrid that is more console/desktop like inside than the Switch is. The little hardware tweaks Nintendo made to accommodate the purpose do constitute its hybrid identity, but they are complementary factors.
Switch's hardware is not that impressive. It's the purpose that made it impressive. Nintendo did the right thing and had it replace both their home console and handheld lines.
PSP and Vita were not intended as home console replacements or successors. Their games were significantly lower budget and cheaper to buy, they didn't get enough ports, and the ports they did get (barring exceptions like Tekken Dark Resurrection) were much more noticeably inferior to home console versions when compared to Switch vs others (this is mainly due to diminishing returns, but it shows that the Switch was perfectly timed).
The PSP hardware was crazy impressive (arguably the most impressive console hardware of all time) for its time, but it just wasn't purposed to be the main character.
