Alchemists were doing research 600 years ago but they never shared their results with others and used arcane syntax to record those results which nobody else could understand. This didn't lead to much progress in the field of chemical knowledge, because it was just continual reinvention of the wheel.
The scientific (and then, industrial) revolution didn't begin until researchers started sharing their results in open literature form, or at conferences, or within bodies like Britain's Royal Institution. Dissemination of knowledge is absolutely part of science.
Similarly, a fundamental necessity in science is independent replication of results, and that's definitely not possible with closed secretive research done in the alchemical mode.
What if the science is disseminated within a closed group? For instance, suppose the classified research is shared with other people with a security clearance. That still wouldn't be science? Or suppose scientists at universities shared their research with scientists at other universities, but not the general public: that wouldn't be science either?
What happens when you have an authoritarian system in place controlling distribution of results, is that everyone in that system quickly learns that if they question the reliability or wisdom of the research, their career is over. So they go along and don't subject the results to the kind of scrutiny science relies on, because making the boss look bad or embarrassing the institution isn't an option in that situation.
There are many examples, such as the secretive public-private DOE FutureGen program aimed at "zero-emission coal-to-hydrogen plants" which wasted about ten billion dollars over twenty years with nothing to show for it (and whose data is still not available), the Trofim Lysenko plant breeding program in the Soviet Union which wrecked Soviet agriculture for decades (and falls into your latter category) and so on.
Another example could be the Challenger Space Shuttle disaster, although that's more an engineering failure than a science failure, but it had similar underlying causes, i.e. managers pushing engineers to go along with a flawed protocol.
That's an echo-chamber, especially if the closed group is consistently aligned in their goals so that they're predisposed to want the same things from the research. The entities would have to be arranged so that they're asserting checks-and-balances on one another.
The scientific (and then, industrial) revolution didn't begin until researchers started sharing their results in open literature form, or at conferences, or within bodies like Britain's Royal Institution. Dissemination of knowledge is absolutely part of science.
Similarly, a fundamental necessity in science is independent replication of results, and that's definitely not possible with closed secretive research done in the alchemical mode.