Printer SHOULD automate duplex printing with software, even when there's no duplexing unit

[BlackieHamel]

I upgraded from a B/W unit from HP to a color printer, but I didn't notice that my new model lacked a duplexing unit. Too bad for me! But I don't get why HP didn't include a software-based option -- how much time would it have taken an engineer to write something that says  (1) put odd-numbered pages in the paper-feed tray; (2) put even-numbered pages in reverse order and put in the paper-feed tray -- and have HP do the rest?

Now, when I want to have a PDF of a back-to-back document, I must create two files and use a third-party program to (1) merge them, (2) reorder them, e.g., for a 10-page document, "1,6,2,7,3,8,4,9,5,10". That's not something a human should have to do every time. 

Am I missing something? Is there an easier way to do this/

[Valsimot]

You are missing a lot. M283fdw has an automatic duplex, and manual software duplex ( printing even and then loading paper to print odd pages ) is like +30 year old function available on any HP printer.