Why do we keep a newswire database that stores these things before being published? Why don't companies and officials not hold on to these documents themselves?
You could say newswire are better at protecting, but the companies who write the press releases will likely have a copy stores both before and after it enters newswire
If you are a registered company (like any publicly listed company in the USA) you need to release important information to as many people as possible in a timely manner. Newswire makes sense since it goes out to 1000s of newspapers and websites. It also makes sense to queue it up before release. Otherwise, that would give people listening to your earnings conference call or checking the EDGAR filings an unfair advantage over more accessible resources.
You could say newswire are better at protecting, but the companies who write the press releases will likely have a copy stores both before and after it enters newswire