At one point.. back in 05/06 someone staed that there were 4 comapnies making laptops in the world.
Prior to the buyout by Lenovo, IBM did not manufacture laptops, they were in the same boat as dell/hp/ etc etc they were doign some design work, but mostly in packaging, and the high end IBM laptops were built well with solid frames.
ASUS is the quiet guy behind the scenes, until the past decade... as you say, they've been in the background making units for everyone else for along time. Our shop was using thier parts to build our own boxes for years before they had thier own branded units on the market.
The problem with PC laptops is consistancy, or rather the complete lack of it... whatever new model Laptop is out there right now, it won;t be for long... models are designed manufactured and EOL'd so damn fast it makes your head spin.... plus your run of the mill laptop will live 3-5 years, if you are nice to it.. yes I know we have all seen ones that last longer, but the live a hard life usually... so the makers of these beasts are jumping from one bandwagon to the next in order to keep new product in the pipeline, therein the high risk of issues with systems in general and even more of these issues in the low end stuff due to profit-margin pressures.
I'll go back to they all suck... lol... Models stay around for 6-12 months... so finding feedback in forums on how they are doing is tough... the media is mostly interested in talking about new, versus being a watchdog on what was... don;t buy a cheep laptop...