With platforms that's coming making things really easy like new devices like net books and tablet making it easier to take around with them, people nowadays want comfort over quality with devices hitting the market really in the market these days, they don't need to tweak or mess over with the motherboard, sound card, video card and etc on goes in a computer. 

I know they're some people that are making custom made computers It does require some technical understanding which isn't a big deal since you can learn that off the internet anyways, which it takes a while I know you learn it very quick, you got to put the time and effort to learn.   I done it before with my last computer, since I been looking a lot of step-by-step instructions.  

You don't have to necessarily pay for classes to have someone to teach you basic anatomy when you got the internet help you out, But does that mean you don't need to pay for classes?...It helps If you have the funds to pay any technical college.  But all this right there is nothing but elementary,  I think a fifth grader can do this anyway if he/she wanted to.  The only question is if he/she has the money for parts and the requirements build one?!  Projects like these are costly and you're going to need a lot of money for

• Tower Case

• Video Card

• Disk Drive

• Mother card (AMD or Intel)

• a fan or liquid cooling (Optional)

• RAM

• Power Supply 

• And a Operating System of your choice (Windows or Linux...Don't know about Mac OS's for sure)

I might be missing something in the list?  I feel did missed something, but I have to look back.  But you'll get the  idea. All you need to do the is your research on your own.  Building own custom made computer maybe easy some but word of warning the parts will cause you around $600-$2,100 or little bit higher than depending on the cost of the parts. 

Back on the subject with PC's I think your going to get some people buying a new PC's,  I don't know if a lot of people are going to purchase one with how the economy is today.  People do want to get out with something that they can enjoy with the palm of there hands instead of being home all day in front of the computer,  You got a lot handheld device which most of them provides WI-FI like IOS, Android tablets and smartphones.

  So it really comes down to your technical needs  What do you prefer? that is the question.