I still have my original 1000 from like 2006 or so, though it's kinda worn and the analog nub is missing. Haven't tried turning it on.

I have somewhat replaced with a model known as the e1000 which I believe was sold in stores under the name PSP street? It has the same size as the original 1000 but it's much lighter in mass, the memory stick is inserted at the top of the PSP (kinda like a DS game card) and there's a tab at the top to flip open the back plate to reveal the UMD drive and the battery, but it has no Wi-Fi capabilities whatsoever, which is fine for me.

Speaking of which, I remember when the original PSP 1000 first came out, it was consider large and heavy for a gaming portable at the time, but these days it seems quite small compared to the Steam Deck and the Switch in handheld mode, but it still feels heavier than the Switch and I haven't even touched a Steam Deck.

Size creep has affected many portable electronics, with phones being the most notable.

From some searches, PSP 1000 has a weight of 280g, Switch is 398g (with JoyCons attached or 297g without), and Steam Deck (original) is around 640g.
The Switch having a lower weight density probably gives it the illusion of being lighter than the PSP.