Who fucking knows what's going on.
I don't doubt Jeff believes his sources, and my suspicion is that his sources are accurate. The statement that certain parties would be confused and annoyed if a March 26th Direct was cancelled or delayed without notice implies that the sources are people close to or within third parties or indie devs. This would fit the long standing suspicion that a lot of Direct date leaks come from third parties with content represented in the Direct, with them often also not having full knowledge of the Direct content beyond their own representation.
Third parties are given prior knowledge of Direct dates because, well, it's their content in it. For marketing purposes third parties will schedule their own tweets and content for Directs to ensure their own social media accounts are on top of the content as it's advertised, rather than supplying Nintendo with a trailer or content and having to guess and wait like the rest of us. If Nintendo were to make changes to the Direct's date, or cancel it entirely, third parties would need to be informed to either delay their own marketing campaign or, in some cases, skip the Direct and advertise their own content ahead of the newly scheduled date.
As I noted earlier though there's also the possibility Jeff has been had the Nintendo Rumour Circle. This is a common problem in this particular ecosystem of fans. Person A works for a developer in some capacity and passes info on to Person B, in this case the date of the next Direct because their content is in it. Person B tells Person C. Person C tells Person D. Person D tells Person E. And so on and so forth. Each person who is told promises to keep the info confidential, does not, and passes it on. And to cover their arse does not reveal who told them, only their "source". If a rumour turns out to be true, Person E celebrates and believes Person D to be accurate (because technically they were), and it trickles up. In this case you have one person who works in the industry and actually knew, four people who don't know shit, but now all five are considered "reliable sources" because they were all technically correct. This issue, of people talking between each other and rumours circulation around and around to the point of losing their point (or points) of origin, is pretty evidently an issue in the Nintendo Rumour Circle and can lead to a single rumour seeming like it's coming from multiple people who technically have a reliable history but only because of circumstance. I'm not suggesting this is the case here. Just hoping it is not, and maybe for future reference as a word of advice for people here and elsewhere to temper their expectations with rumours because I'm telling you, I promise you, this happens.
Lastly, if all of this is accurate, Jeff's sources are bang on the money and nothing has changed, the only options left are a shadow drop or very quick turnaround between announcement and reveal. It'd be unusual but, in the same breath....why not? Nintendo has dropped entire Directs, usually singularly game focused, onto their YouTube account before without it being streamed or controlled. An argument could be made that a shadow drop would be less stressful to YouTube's bandwidth than the announcement of a stream, as instead of tons of people knowing a date/time and showing up all at once, a shadow drop will slightly reduce load by staggering influx of viewers.
But I guess we'll have to wait and see. I'm banking on Jeff's confidence that, at the very least, there was intention for a March 26th Direct. I don't think he's talking shit, and I think he has good reason to believe his sources. Whether or not they're still valid is another matter entirley.