That is easier said than done for a lot of reasons and would probably result in less accurate data. They would have to get the respondents ( households and businesses) on board. Putting the burden on the survey takers could result in fewer completed surveys and less representative data.
You need economists and statisticians to analyze trends, make adjustments, etc.
Dating cleaning and validation are not as easy to automate as one would expect as different data issues come up all the time.
In summary. They could automate everything to an extent, but it would give you less reliable results. The delays and revisions might give the perception that the results are not reliable, but they actually make the results more reliable.