You can download more RAM though.

Sure, but minimal gains still add up to more efficient use of what's there now. I see that as a win.

the displays are not interchangeable, most internals are completely different.

You can buy a screen from https://deckhd.com/ it is still an IPS display but this one apparently covers a higher color gamut.

That's not what they said, though. That might be how it was characterized in whatever retelling you heard, but their comments have always been very specific that a new, more powerful successor wasn't coming any time soon. They never said anything implying they wouldn't update it at all.

This is the same performance target, just with a nicer finish.

It's wild reading comments like these, because I thought they made it painfully obvious. All the headlines from that interview clearly delineated that they were talking about a "faster Steam Deck" aka a Steam Deck 2 and not a hardware refresh. Like here's a Verge article from September

"changing the performance level is not something we are taking lightly... I don’t anticipate such a leap to be possible in the next couple of years"

All that said, Valve might totally still have a Steam Deck refresh in the works that doesn’t change the performance floor. There’s a rich history of console manufacturers releasing smaller, lighter, and more power efficient versions of the same hardware...