DR DOS 7 did have built-in peer-to-peer networking: Netware Lite.

MS DOS did not, because that was the main selling point of Windows for Workgroups.

Yea, there was alot of features that one is used to in modern OS that was missing in MS-DOS. It does not mean those features didnt exist or wasnt being used.

We used 3rd party TSR drivers for it.

Examples:

- MOUSE.COM driver https://www.vogons.org/viewtopic.php?t=58777

- CDROM driver http://manmrk.net/tutorials/DOS/cdrom.htm

- Network stack https://en.wikipedia.org/wiki/IPX/SPX

- Graphics driver https://dosdriver.de/graph.php

- Sound card drivers https://dosdriver.de/sound.php

Some of these things were included later on.

For instance:

DR DOS 6 had Netware Lite; DR DOS 7 had Personal Netware.

https://en.wikipedia.org/wiki/Personal_NetWare

I think several versions of DOS included MSCDEX.EXE (or DR's equivalent), but not the device driver, because back then there were lots of different CD interfaces: Mitusmi, Panasonic and Sony on sound cards, some early EIDE ones, and SCSI on higher-end kit.

Mouse drivers came with your mouse. ;-)

MS did have a network stack bundled for free on the NT Server installation CD, and some versions of it support server mode for peer-to-peer operation.

DOS could do all this stuff, but you had to assemble the bits from different sources, and this was sometimes for good reasons, sometimes technical (a profusion of incompatible CD-ROM interfaces) and sometimes commercial (P2P LAN support).