MTBF man, MTBF. That's the reason to spend money.
Cisco bought LinkSys so they could compete in the LOW END segment. Same reason that Bay (now NorTel) bought NetGear, and before that, SynOptics. They wanted an off-brand that they could sell for less money, and rather than engineer their own, they just bought one that already existed. Just because they're owned by Cisco doesn't mean they are quality. Acuro is owned by Honda, isn't it? Are you trying to tell me that a Honda Civic is just as good as an Acura Integra? I didn't think so.
As for why CCIE's make in the hundreds of thousands of $$, can you do it? Supply and demand, man. There aren't many of them out there (less than 50,000 worldwide, IIRC). So of course they're going to cost more. Just like everything else. If they are highly desired, and there aren't many of them, it's going to go for a premium. As for why companies hire them, it's because companies that NEED them are large enough that they have ever-changing networks and they need superior performance, and they need someone who knows the stuff like the back of their hand, EVERY day. ISP's and REALLY big companies are the only ones who need CCIE's on staff. How many CCIE's have you met? I've been in IT for a little over 6 years, and I've only ever met ONE CCIE. He was a contractor. I don't know any that are permanently on staff at ANY of the companies my buddies work for. Do you?
However, it doesn't take a CCIE to configure one switch and one router... I'm not even CCNA and I can do that..