Do you think the government would be able to get away with altering data after the fact? If they released it, someone downloaded it, and would be able to easily spot changes. It could even be (and probably is) automated.
And either way, what does the blockchain offer if the government comes out and says that some previously published numbers were incorrect, and they publish new ones? You'll have two competing versions of the same data, with one considered obsolete because the government says so.
And none of this matters if they're altering the data before publishing.
Revisions to initial economic data is common, though, once other slower statistics are compiled into a final GDP/CPI number. The initial month-over-month or QoQ are estimates.
Why alter it when you can call it fake news and fire the person who published it and hire a new person who is commited to "Fair and Balanced" data*
*data is for 'entertainment' purposes only - Names, characters, places, and incidents either are the product of the author's imagination or are used fictitiously, and any resemblance to actual persons, living or dead, or actual data is entirely coincidental.
