Until it doesn't. I can open my Thinkpad (W530) and replace parts in it that die. Can you say the same for your Macbook? Are you okay with a future where everyone follows Apple's example because it generates more profits, where right-to-repair is a thing of the past? I know that sounds alarmist, but it's definitely the trajectory I see.
So yea, Apple their gravy train is going to run into a massive road block. In the US states are also starting to rectify laws that push the right to repair.
Its one of the reasons why Apple "suddenly" allows repair shops to buy parts. As a way to change the narrative. Of course that buying parts has "issues" Apple style. A grifter is going to grift.
As to your second point, MacBooks have been available for how long now? And yet thinkpads still exist.
The X1 Carbon doesn't have upgradeable RAM. On some level, I'm convinced that Lenovo wants to follow in Apple's footsteps and is testing the waters with the X1 Carbon series.
Since the new Air lacks even a fan, it seems even less likely to need service.
Practically speaking being “locked” into a system would only be a possibility in a world where highly distributed, massively supported OS’s (Windows, Linux) didn’t exist.
Anti-apple people have a hard time fathoming the degree to which many other “power users” are okay with privacy/security trade offs if it results in a more robust/stable environment that just works.
Problem is, it’s being framed as some sort of Faustian bargain when it’s really not that big of a deal.