What are the main challenges in Linux adoption for New users, and how can it be addressed?
I'd say its probably, among other thigs, hardware compatibility issues.
Running Linux on a mashine, most notably portable, that is somewhat recent and is not specifically built with linux in mind is, imo, almost certainly going to cause some, for the average user unfixable, issues. Things like wifi, bluetooth, audio, etc. not working due to missing or broken drivers.
The best way to fix that would be official Linux support by the OEMs, which realistically is never going to happen. Or extremely time consuming reverse-engineered community drivers.