OEM's (i.e., manufacturers like HP) are notoriously bad at keeping drivers up to date. They still live by the 80's mantra that you get what they sold you. What makes it worse is the fact that OEM hardware often isn't supported by chip manufacturers and their constantly updated drivers. For instance, you're very unlikely to be able to use an Nvidia graphics driver for an OEM Nvidia card. The trick is to find community sites who tweaks the updated installer files to enable them to install on OEM computers. They're basically customizing the driver's inf-file to include OEM branded hardware. I can't remember the specific sites providing these drivers so you'll have to tread carefully if you decide to go hunting custom updated drivers.
The reasoning brands like HP use to defend their "incompatible" drivers is that they need to do this to make sure drivers are compatible. The lie-free reason is that OEM's pays a lower price for components than non-OEM's. The way they get this lower price is partially by agreeing to opt out of driver update programs catered for by chip manufacturers like AMD, Intel and Nvidia.
Anyways, I would also say that you should be extremely wary with those paid for driver update utilities asking you to give them money to update your drivers. There's no guarantee they really do update your drivers. If they don't they'll just take your money and say everything looks dandy on your PC.