How many laptops are ever upgraded? You're stuck with the original processor and whatever wear and tear the thing has accumulated. I know I have a small stack of obsolete or half-dead laptops from across the years, and the only upgrade that was ever worth the hassle was hard disk -> SSD.
The "just works" aspect is extremely useful for non-expert users.
I know I have put extra RAM in laptops and once brought a new battery. You are correct in that you are limited to the chipset that came with them, but HDD->SSD is not a trivial upgrade.
I keep thinking about older ThinkPads with Core processors - there is a huge aftermarket with many original parts, many of those notebooks are basically on the level of contemporary i5 notebooks with thicker body and worse screens, but with upgradeable RAM and storage. And you can have them for the price of current Chromebooks.
If a trend in the industry is towards limiting upgradeability, in the direction of rent-seeking by first subscriptions, soldering everything onto mainboard, limiting connections, later perhaps rental fee for equipment like it is with car leasing, a trend which I consider insane, can't I object to it? Chromebooks are basically a prime example of this trend, while regular notebooks didn't embrace it fully yet, but are getting there as well. Can't a company with arguably the best predictive platform in the world model and foresee the effect on environment, or is it just profit and mindshare that matters these days?
The "just works" aspect is extremely useful for non-expert users.