Because it's a platform under active development, and they're probably more concerned with functionality than some super sexy tiny cooling solution? At some point they'll most likely test the production cooling system, but for now it probably doesn't matter. You'd be surprised how many things (cooling, PCBs, etc) are much larger early on than their production counterparts...
Software perspective: Fatal error, I'll just make a change and recompile.
Hardware perspective: CPU cooked itself because frequency regulation was accidentally turned off, time to wait for new parts from China + assembly.
It always amuses me how laisez faire folks are about things like ESD. "It's never caused a problem before" isn't a reason to ignore best practices and not work defensively.
So the i.MX 8M SoM package will be smaller and dissipate less heat in the final handset?
I wouldn't expect the same chip going into a smartphone to require a heatsink or any thermal consideration at all on a sparsely populated, open-air circuit board.
It could be that power management is not enabled yet, or perhaps other thermal protections are not fully enabled yet. I doubt the SoM package itself will get much smaller, but I'm just basically guessing since I'm not an employee of Purism.
