"I wonder if it's possible to create one."
Websites are usually hosted on a single server but with a content delivery network they can cache the website when it goes offline. The problem is that a blockchain is just not as efficiënt as a centralized server. You can never get the same high speed and cost effectiveness, but they are more secure.
Right now, there are much different front ends for Steem.
If steemit goes offline we have busy.org, partiko, steempeak, ...
It's probably a better solution.