Just so everyone who comes here to pile on with the ignorant/stupid opinion of "this doesn't matter for most users" fully understands the longer-term ramifications of this decision by Apple, I'm going to explain it to you simple-like:
We aren't talking a mere 5% or 10% difference in performance here; we're talking half. Or a quarter. Testing shows that users, generally, can only begin to discern performance differences when they are above ~15%. If you sit down to a CPU that's 10% faster, you won't likely notice. 15% slower SSD, probably won't notice. Half? You'll notice. Quarter? Oh, yeah, you're going to notice.
Now… that depends on ONE THING: relativity! The user has to have relative knowledge: using the slower system AND the faster system. Most users don't have that luxury… they have THEIR system. So, yes, for "most" buyers, they're not going to know Apple screwed them. Not for another 4 or 6 years. But, by then, they're already expecting whatever is new is faster, so they don't "feel" it. ("Feel" it as having been jilted in the "value proposition" from their prior purchase.)
But… make no mistake: Apple isn't sitting still. Tech isn't sitting still. Development isn't sitting still. In 3 years, everything is going to be fatter… macOS, apps, what users do as they progress from "newbie" to "advanced" (their expectations literally expand). What runs on 8GB of RAM fine today, won't. What runs in 16GB, barely will. macOS will start hitting that storage more… and more… and more… and more often. The storage, through "aging", will itself begin to slow down. That "half" becomes greater than half. "Quarter", greater than 75% slower. Meanwhile, Apple's devs are designing EVERYTHING for the NEXT Mac Apple is going to release and make another buck on. Developers are buying the fastest thing Apple sells because they can afford the "value proposition" as a business case. And those units aren't single-channel or dual-channel. And they won't be 3 years from now.
And aren't we HOPING that newbie users love their Mac so much they learn new tricks? And that the Mac they bought has an entire previously-untapped amount of performance that magically empowers them to do greater things? Hasn't that been Apple's whole schtick??!?
That user with a single-channel 256GB M2 Air or mini? Who bought that model because it was they can afford? They're screwed. Poor? Haha, screw you. Grandparents went to Best Buy or the Apple Store and bought you the base model, because that's what was on display with the price prominently advertised (because it makes Apple the most profit)? Too bad, so sad. Good luck with 5 browser tabs open on macOS 18… Pap shouldn't have been such a cheapskate. Spent the extra for a 512GB mini M2 Pro? Nice try… should have forked over another $200 for 1TB… you didn't tithe ENOUGH to the Apple gods. Ha-HA. Scraped everything together to get a "Pro" MacBook? Sorry, you're just "Pro-sumer", not "Pro"-ENOUGH.
Eventually, these users will start to think "Wow… Macs aren't so great, mine is slow, just like my friend's PC." "Macs aren't better long run than (garbage) PCs." "Why am I spending a premium for Apple crap?"
And they won't buy a Mac again. Maybe ever. Bye-bye Mac market. (D'OH! And Mac global market share is currently back below 10%, like it was in the 1990s when Apple was "dead"?? You do NOT say!)
Worse, for ALL of us, is that the colleges and businesses that REALLY don't care—again, they've accounted for that "value proposition" and are fine with buying new PCs every 3 or 4 years, so they're not gonna get stung: those units mostly go into landfills. Yay, PLANET! (And, even on the refurb market, who is going to want a 256GB mini in 3 years that has storage slower than a 8 year old 2018 mini?? Landfill. So much for the eco cred.)
And why? Because Apple is saving $5 on a $1200 or $2000 piece of "luxury-brand" hardware, hoping the market is full of ignoramuses. Counting on it. Banking on it. Preying on it.
I'm sorry… #NotMyApple. F this greedy-beyond-belief Exec team. Apple customers deserve better… no matter how much money they have to spend. And this isn't my opinion! It is what Apple SAYS on stage. We should, at least, be holding them to the PR they spew. If you don't, you're just dumb. And I'm not sorry: dumb people don't deserve the Mac (and the corresponding community that I've spent my life improving)… go buy a garbage Windows box and get out of my ecosystem. Please.