Sure, and people will make the argument that taking the bus is much cheaper than taking a limousine, when comparing methods of transportation. However, people aren't generally comparing pricing between limousine company A and city of X public transit, and wondering why one is so much more expensive than the other. They're going to compare limousine company A with limousine company B instead. If all you need is public transit, then by all means use that method of transportation, but there are times when a limousine service may be called for.
Likewise, if all you need is an unmanaged dedicated server, and not a managed server then great. Yes, it's going to be much cheaper than a managed hosting company, as it doesn't include server management. Just as a car rental doesn't include a chauffeur. But if you're honestly shopping around, you should be comparing one unmanaged dedicated server provider to other unmanaged dedicated server providers. And you may not, but I would also make the distinction between budget unmanaged providers and premium unmanaged providers. There's little point in comparing OVH to SoftLayer. Just because OVH is much cheaper doesn't mean SoftLayer offers poor value, not that I'm arguing it doesn't. OVH's network has limited transit options, has frequent congestion issues, and much higher latency transport links. They also use desktop grade hardware, which are much more prone to failure. Anyone heavily involved in the hosting industry is well aware not to host anything mission critical on OVH's service, and those that do are well aware of the risks involved.