There are details you might be missing. The SC went so far as to meet w/ Nathanial personally on July 5 and waited on pronouncing on PEP 654 until he was able to provide more details on his alternative proposal to accommodate him. This was after the initial PEP was posted back in February and Nathaniel participated then as well. So the timeline isn’t 28 days since this topic was opened, but 7 months (the co-authors of PEP 654 have been very patient waiting this long for the SC to make a decision).
Also please go back and read Accepting PEP 654 (Exception Groups and except*) for why we don’t think waiting longer for Nathaniel’s response was going to change our minds on his alternative proposal. But also note we left the door open for changes if a compelling case can be made even with our acceptance of PEP 654 based on lessons learned from implementing the PEP.
Dates can sneak up on you. 
b1 means initial implementations need to be done, stdlib needs updating, docs, discussion of all the code and APIs have to be resolved, we have to agree that nothing is changing, etc. Add on to the fact that this all takes a while due to limited volunteer time for everyone involved and it makes the timeline not as expansive as you might think (for instance, I don’t know what people’s vacations are like between now and then, people change jobs, have kids, etc.; remember the co-authors submitted this back in February when their availability may have been widely different than it is now). And if people want to argue that PEP 654 doesn’t work then nothing beats having live code showing how it doesn’t work and how there’s a better alternative (hence why we said we are opening to changing things if it makes sense, but we think getting PEP 654 implemented now is a good thing).
Delaying the decision longer also assumes the SC would have enough time to review any alternatives to give enough time for landing anything for 3.11b1 (this already took so long that this missed 3.10 even though the PEP was written over 2 months before 3.10b1).
Do understand it’s not just Nathaniel’s schedule, but all all five members of the SC and the 3 co-authors of PEP 654 we have to try and accommodate as well.