John Carmacks quote becomes more pertinent as time goes on because computing power is only becoming cheaper. And to directly address your point, the common person now has access to more computing power than ever before at a cost lower than ever in history because of the cloud.
If anything the barriers to entry continue to drop leaving only our lack of persistence as what stands between us and success.
The demand for servers and compute power has increased because of the cloud. Just because server rooms have turned into datacenters does not mean they "shrunk", quite the opposite.
Some types of free services that go out of their way to build traffic at the expense of revenue, or computation intensive services like real time audio/video may be exceptions to that rule.
Some anecdotal evidence - I ran a cacheless Django site that more than made the server costs back monthly via a single Adsense unit, in the gaming sector where eCPMs are rubbish, and the files you serve are huge, and the server was never at any point at more than 20% utilisation.
By and large, the cloud has lowered the barriers to entry. Unless you're running Justin.tv, server costs are down in the noise. Getting users is the hard part; serving them pages is not.
Cheap PCs in your basement, or cheap VPS machines are perfectly acceptable for starting out. Also, if you're conscious about performance and have good bandwidth, you can serve insane amounts of traffic from a single server.
Cloudwise EC2 is trending down, Heroku starts free with reasonable limits, and VPS with 500M memory at Linode is $20/mon.
http://aws.amazon.com/about-aws/whats-new/2012/03/05/new-low...
