AP and Reuters pay people to check the results locally. Between them, they feed a LOT of outlets. A significant amount of the data is available online pretty quickly, but some states and localities simply don't publish the data in a timely manner.

Some news organizations will have their own staff checking results, especially in areas where it is known that the results will be slow and the results are going to be within polling error margins.

You'd think the data could be crowd-sourced more effectively, but private citizens get the data more slowly for a few reasons ... First is that there is red tape involved in obtaining the data (i.e. forms to fill out, fees to pay and it all must be done ahead of time) and second is that after-hours early access to data is just plain limited logistically. If it could be efficiently delivered to a large quantity of people, it would be presented online.

There are a few areas where the government decides that it's more efficient to let private parties distribute data, and it's generally pretty good business to become one of those parties. NMVTIS data comes to mind immediately (carfax and it's competitors), but there are many similar instances.