The CPU is not socketed/replacable because intel simply does not sell socketed laptop CPUs. If there was a socketed alternative, I'm sure it would be in the framework.
What is the distinction between 'laptop CPU' and 'desktop CPU' if not BGA (or whatever it is) vs. socketed packaging though, really? Power consumption?
Wouldn't it be nice if there just 'CPUs', and you could pick whatever was appropriate for your desktop or laptop. Sure some would maybe only make sense in one package, but there must be some considerable overlap. I use my desktop for work because it has upgradeable RAM and I needed to do that, not because it has a beefier CPU than is available in a laptop.
Yes, it's mostly power consumption and efficiency, with the puny heatsinks found in most laptops, you can't cool significant amounts of power without throttling. Having the CPU on the motherboard also allows for a thinner assembly. I don't think having a socketed CPU just for the sake of it would have been a good choice here.
Yes, power consumption, and, relatedly, heat dissipation. You'd probably get unusable battery life in a laptop with a desktop CPU, and need a lot of fans to cool it.
Wouldn't it be nice if there just 'CPUs', and you could pick whatever was appropriate for your desktop or laptop. Sure some would maybe only make sense in one package, but there must be some considerable overlap. I use my desktop for work because it has upgradeable RAM and I needed to do that, not because it has a beefier CPU than is available in a laptop.