the reasons behind the cisco rollover cable pinout

Inversed with respect to what?

Here is how it works.

There are two kinds of cable:- Rolled and straight.

There are two kinds of headshell:- "Terminal" and "Modem"

If you use 2 x X pin "Terminal" headshells (X = 9 or 25) and:-

1 - straight through cable you get an X pin D to X pin D straight thru cable. 2 - rolled cable you get a null modem cable.

Changing 1 headshell to the other type is the same as changing the cable to the other type except that Modem headshels are male and Terminal ones female.

The newer "blue" cables with the molded on

9 pin are equivalent to a rolled cable and a 9 pin "Terminal" headshell.

I have never seen a 9 pin "Modem" headshell. Modems always have 25 pin female connectors.

This cabling system was invented when router console ports all had D type connectors.

The RJ45 connectors consoles were conveniently fitted into the existing system which of course includes the Terminal Servers and the Octal cables that they use.

Of course there is always the Cat 5500 supervisor 3 (IIRC) debacle where some poor soul used the wrong pinout making it the odd one out. That mistake has not been made again.