Even if you could expand the RAM and storage,

You can.

everything else is just sitting there waiting to be obsolete in a couple years.

That's what some people said about the Steam Deck. More than a couple of years later, it is still popular; clearly not obsolete.

I just don’t get who they’re trying to make this for. You can easily build a PC with a reasonable budget that could easily tackle things this cube probably couldn’t.

I think you're overlooking the fact that most gamers have different skills and priorities than yours. Not everyone would find it easy to build a computer at all, let alone build a quiet and compact one with well-matched components, a tuned and convenient OS, and good support.

This device is probably not a good fit for you. It probably is a good fit for many people outside of gaming PC enthusiast circles. Especially now that Valve has established its hardware as a well-defined platform for game developers to support.

everything else is just sitting there waiting to be obsolete in a couple years

a bit out from the cutting edge, sure, but obsolete? This aint the 90s or the Aughts any more.

A machine put together 10 years ago will still run most things fine. Not at the fanciest settings, but fine. This is essentially the same criticism PC gaming has been lobbing at consoles for years, and now we have essentially a PC masquerading it's way into the console wing of the market -- of course the same criticism still apply! It's not incredibly beefy because it doesn't need to be. Different audience, different requirements.

It's supposed to be a console. You connect it to your TV and it more or less just works. Like a PS5 or Series X, except it has more games. The entire thing consumes about half the power of just my low-end graphics card from a few years ago (3060 ti). These CPUs also aren't available as socketed versions, nor would it be a good idea because then a user might use a chip that generates too much heat compared to the design here.

This ISN'T meant to compete with a PC. If you already have a gaming PC, you don't want a Steam Machine. If you have a current gen console, you probably don't want a Steam Machine.

There's a lot of speculation as to the price. If any of the guesses from various outlets end up being true, it could be less than $500 and potentially less than $400, while there have been hints at the next generation of Xbox costing $1000. But this is all speculation.

Basically, it's a way to get into gaming with a console-like experience, a low price, and the ability to keep your game library when you evolve into a "real" PC gamer. Honestly, if my kid was old enough to get into gaming, I'd consider one. Genius move from Valve targeting specifically a market previously untapped by them - not us folks who already buy our games on Steam.