Because you are stuck with the hardware you bought! I have had Macs for a while but I think my next Laptop will be a Framework 😁
Does the Framework offer any ARM processors though? Or are they stuck on x86-64?
What are your use cases for Windows on Arm? Or are you planning to run Linux?
Since its a laptop, I personally look for a modern, efficient architecture that will have a long support cycle and has the capability of supporting a very strong OS that values my privacy and security. I typically just use a laptop for surfing the web and checking emails, so nothing intensive.
As far as OS choices:
Windows does not meet the privacy criteria for me, unfortunately.
ChromeOS also does not meet the privacy criteria.
Some linux distributions offer the necessary packages, but typically aren’t configured by default. You have to go through a very thorough hardening process to set it up properly, but it is possible.
MacOS does meet these requirements, and I generally recommend macbooks to people who have my same use case.
In the case of Framework laptops, I would go the Linux route. Probably Arch Linux with a strong TPM + Secureboot and hardened unified kernel setup.
These are just my personal requirements, and I understand they may not be the same for others.