Oh, that's certainly not true.
Sorry, but it really is. The vast majority of laptops these days are cheap thin-and-light-ish designs, and nearly all of those have soldered memory - it's cheaper for OEMs that way, and it's easier to charge a premium for a thinner laptop. There are still many models with replaceable memory, but they are increasingly rare.
May not be, but no one predicted that 512MB wouldn't be fine once Vista launched either. Things like that are hard to predict well and putting upgradable RAM doesn't make laptop any meaningfully thicker. At most it adds 2-3 millimeters of thickness. And it doesn't cost them anything meaningful to make RAM slot. Also laptops with already big RAM capacity carry a huge premium and we all know that they ware only charging that, because less aware of things, buy those things. Soldered RAM is anti-consumer BS and serves no purpose existing on something as big as laptop. Soldered RAM is only acceptable with truly small devices like single board computers, Arduinos, tablets, phones, but not laptops. If I wanted all soldered crap, I would go to Apple to be screwed. A PC is personal and should remain so.
Nice straw man you've got there. It's just too bad nobody has been arguing for what you're arguing against here. Again: you're arguing a systemic, industry-wide point as a specific criticism of a single device. Do you do the same for every thin-and-light laptop announcement? If not, then please take your selective logic elsewhere. And as I said before, this is a device that, unlike those laptops, actually makes use of the density provided by soldered RAM. The size increase from sticking two SODIMMs into the Steam Deck would be
far beyond 2-3mm. That's less than the thickness of a single SODIMM+socket, and you'd need to design the motherboard around fitting them, change the cooling system layout, etc. I generally want things to be as repairable and upgradeable as possible, but this is really not a good device at which to draw a line in the sand on that subject. Seriously. This is a case where the lack of upgradeability is
acceptable, as it has good reasons behind it. It's a
really weird place to complain about it.
I dunno, Turion X2 TL-60 was adequate for me in 2017. It had two AMD K8 cores. It was basically better binned Athlon 64 X2. It's fine for web browsing and doing things. It wasn't really slow for me. I only saw big difference between it and FX 6300, once I launched WCG to crunch, but even then it was nearly as bad as I thought it would be. After all it was scaled down full desktop chip with only slightly lower clock speed. It surely was better than stock Sempron 3400+ working at 1.8GHz. SSD helped a lot to make system feel responsive. But it's important to mention, that it depends on your usage. If you want any demanding productivity, I would likely feel a lot more held back. The worst thing about that system was by far e-waste GeForce Go 6150. So ewaste, that is several times slower than FX 5200, which was first real modern potato. The only nice thing about it is that it overclocked a lot, but that still meant UT 2004 ran at lowest settings at 640*480 and average of 40 fps. It can't even decode anything interesting either.
Well, I guess your standards for performance were pretty low? The i5-540M (with 16GB of RAM and an SSD) in my X201 felt decidedly slow when compared to both my OC'd Core2Quad Q9450 and my later Ryzen 1600X. It was fine, but not good, and my workflow was noticeably improved when I upgraded in early 2019. That is in a use case including multiple browser windows with ~10 tabs each, a few Word documents, plus Outlook and a few other essentials running at all times. It was obviously entirely useless for gaming. But case in point: while I bought that laptop as a base config with 2GB of RAM and upgraded first to 8 right away, then 16 later, 16GB has been sufficient for light to moderate use for a decade. (I never really needed more than 8 in that laptop - it was more of a "why not?" type of situation.) I just moved to 32GB on my main desktop, and often exceed 16 in use, but ... that's with 100+ browser tabs, four game launchers, and a heap of other background tasks running at all times. The Steam Deck wouldn't have any of that running. It's a gaming device first and foremost. 16GB will be sufficient for it for the foreseeable future. Heck, it matches current-gen consoles, so it'll likely be sufficient for console ports for their lifespan, i.e. ~7 years at the very least, though of course the GPU won't keep up for nearly that long. It doesn't have to either. The Switch has demonstrated beautifully that you don't need cutting-edge hardware to make for an enjoyable gaming experience. Nobody is promising years and years of AAA gaming on this thing. It's promising a good play experience with current games, including current AAA games though they might only see 30fps at 800p. Later AAA games will obviously become too demanding for it to run at some point. As is the case with all gaming PCs, consoles, etc.
And again: the Steam Deck isn't trying to be a laptop. It's a gaming handheld that happens to be a small full-fledged PC. It's significantly more powerful (at least on paper) than existing alternatives in that category, such as the Aya Neo or the OneXPlayer. You can dock it and use it as a PC if you want to, but that clearly isn't a main use case. It's for handheld, portable (or just lying in bed/on the couch/in a lounge chair/on the porch/whatever) gaming. Even a small gaming laptop isn't suitable for those use cases - unless you enjoy having a large, heavy, hot laptop in your lap, that is. Most of us really don't. I don't want a big, heavy gaming laptop. I want something portable, easy to use, Switch-like but capable of running my PC game library. And I think most other people interested in this do too. It's not meant as a primary gaming device (unless low-end gaming is good enough for you, in which case that's obviously fine too). You're treating this as if it's trying to be something entirely different from what it is. I understand that you don't see the use case, but ... please try to understand that other people than you have other wishes, desires, use cases, lives. Your tastes and preferences are not universal.