Its just not cost effective knowlege or not.

For example: you will need a business bandwidth from an isp service provider US Average for "home business" around $150 - $250 bucks a month. Then you have the server for a medium grade server your looking at around 3k and a good one is 6k. Just bought one at work for 6k that is a beast. Then you issues with power outages a good ups which is expensive only supports a server for around 45 mins at best under full load. They are only build to keep a server up long enough for a backup generator to kick on. Then you have the issues with your dns and setting it up correctly and getting traffic routed to your dns server. You will need a firewall server as well if you want to really secure the sites. Then there is cooling while one server is usually able to self cool its going to heat up your basement better then your house's heating unit. If you live in a warm client this means pointing your a/c at the server. So to recap your looking at:

$150+ bandwidth a month
$3,000 for medium server
$4,000 for sql license (can go with cheaper options but you lose features)
$1,000 for dsn server / firewall server
$75 a month for that extra A/C unit sticking in the window

Total: $6,000 startup costs and $200 a month maintenance costs.

OR you could lease a dedicated server which would run about 100 "moderate" sites for around $100 bucks a month. If you really had a huge empire business enterprise company you fully wanted to support you can get top of the line best around dedicated servers for around $1,300 a month.

So its really not about knowledge or ability. Its purely just not cost effective at all.