Why isn't there a simple way to add a catchall alias to OpenSMTP ?

[Beau Ford]

I thought this would be very simple ... I would add a line like this to my 
aliases file:


@       username


... and all email addressed to a nonexistent username would, instead, be 
received by "username".

This is what a catchall email address looks like and this is a very 
simple and reasonable to expect this to function.

Smart people reading this already know that the '@' alias is not allowed 
in the opensmtpd aliases file and that what I have just described WILL NOT 
WORK.

But why ?

What is the danger here ?  How does this break things ?  What terrible 
evils will I release upon mankind if I were (gasp!) allowed to specify an 
'@' in my aliases file and just go about my business ?

As it stands, my very simple, very readable smtpd.conf file which does not 
use a virtusertable and does not reference "virtual" anywhere now needs 
all kinds of extra complexity (double the number of lookup tables, etc.) 
just to add this one, single catch-all.

Also, FWIW, I am on attempt number four of cramming virtusers into my 
setup that doesn't need it ... and failing.  My five minute task of adding 
a catchall email is in hour number four and it still doesn't work.

-->  Why ?  <--