That's because most of these so-called 'leaks' are people just guessing or making things up. If they'd had real inside information, then they should known about the M1 mini in advance.
Leakers don’t get a spreadsheet of everything Apple is going to announce, and a Mac mini doesn’t typically spark interest for most people. If, say, someone got an M1 leak from the final assembly factory, the leaker may not even know about the Mac mini as their assembly line is just notebooks. Apple is very compartmentalized, so people working even on the same product don’t always know what the other is doing.
Like the chip team doesn’t know what products their chips are going into, but they do know chip specs. So that’s why Gurman has reported the specs of the M1X but is not certain on what products will get the M1X.
Many of the more prominent leakers have a good enough track record at this point to prove they do have insider information. For example, Prosser created mock-ups of airtags and airpods max months in advanced and they were almost identical to the actual product.
Kuo is definitely guessing too. What happened to the mini-LED 14" Macbook Pro that he said was launching in 2020? Or the 27" iMac Pro that he claimed was coming out in Q4 2020?
Gurman seems to be pretty good with phone predictions, but most of his Mac predictions haven't actually happened yet.
Neither predicted the M1 Mac Mini.
Things change all the time. Kuo is a supply chain analyst so while he has a decent record, his information is not always the most current. He gets his info sometimes years in advanced which means things will change sometimes (especially if there is a worldwide pandemic and supply chain issues). Apple has been know to make last minute changes to software, or delay release of a product. So even if a leaker gets something wrong, it may have been accurate at the time of the leak.
Also for anyone interested, appletrack.com has a decent (semi biased) track record of all the major leakers. Of course take it with a grain of salt.
