Right, I love that diode arrangement.

It reduces the current dramatically since you don't need that 100Ω resistor.
The "Fail-Safe resistors can be much higher values too, I used 2K on mine.

And it allows a "Star" network where you can connect devices anywhere on the buss, instead of a long multi-drop network with a terminating resistor at the end.
And the more devices you connect, the better the signal gets.

Can't imagine why anyone would terminate RS485 any other way.