The NSA is either useless, compromised, or both

In the month leading up to Trump's idiot coup attempt on the 6th of January 2020, the phrase 'storm the Capitol' was used 100,000 times on various forums. The NSA's job is

[...] global monitoring, collection, and processing of information and data for foreign and domestic intelligence and counterintelligence purposes, specializing in a discipline known as signals intelligence (SIGINT).

The US national intelligence program appropriation for 2020 was $62.7 billion: the NSA and related agencies are not short of funding.

So why on earth didn't they notice what was happening? Either they are, simply, useless at the job they are meant to do or they did notice what was happening and either decided not to tell anyone or were ignored when they did.

The second possibility is perhaps more frightening. It is very obvious that there has been infiltration of various US agencies by nazis¹: if the entire intelligence system has been compromised then there is a very serious problem, something quite close to the denazification of Germany after the 1939-1945 war. Except this is much worse: the denazification of Germany was done by the allies, who could safely assume that they were not themselves significantly infested with nazis, while this time no such assumption is safe. Trying to denazify US institutions will be rather like what happens in a scanner darkly, where nothing and no-one can be trusted and no information can be assumed to be reliable.

In fact, this has to happen whether or not the NSA actually has been compromised by nazis, since other organisations certainly have been.

Alternatively, perhaps the NSA has not been compromised, in which case it is simply useless: missing something this obvious is a catastrophic error. Well, it was obvious when Snowden stole a vast trove of information from it that the NSA was an extremely expensive joke: perhaps, seven years later, it still is.