Except that's pretty much what happened with the 2013 trashcan, the 2017 iMac Pro and the 2019 Mac Pro.
Lost sales are a two-edged sword - especially when it comes to commercial users who might actually need to plan & budget ahead. Yes, some will put off buying for 6 months, others will say "OK, I can't wait" and go out and buy Intel or M1.
Also, Apple really now need to show the world that they can scale-up the advantages of the M1 over low-power Intel chips to something that show the same advantages over 10-core CPUs and discrete GPUs with >> 16GB RAM.
...and if there are any significant hardware changes that affect developers, they have to start telling developers about them soon, at which point any secrets will be out of the bag.