Dell learned the hard way about cutting out the discs. They never shipped one-button recovery discs like Compaq used to. Instead it was always the Windows disc, the "Dell Resource CD" and some more driver/software discs.
In 2005 or 2006, I forget which year, they stopped shipping the discs by default because they decided the built-in recovery worked well enough. I started working there in 2006 and they realized they needed to start shipping discs again. We used them for fixing problems or of course just reinstalling when all was lost, so we ended up sending them out like candy. If we needed to use one and we realized the customer had an old version of the XP disc without the latest service packs we would send a new one. We also sent them if the customer asked.
Why Dell didn't also supply discs that did what the recovery partition did I can't guess accurately. They never seemed to mind sending out endless replacements for the numerous discs you needed to do everything manually (assuming they had discs available).
I haven't used a new Dell machine since 2008, so I can't say anything accurate about what they include now.