Yes, you are correct. Ubuntu 10.04 DVD version had both alternate installer and Live Mode.
The download page was clearly saying this
The combined install/live DVD allows you either to install Ubuntu permanently on a computer, or (by entering 'live' at the boot prompt) to try Ubuntu without changing your computer at all.
Also by looking at the file lists of the 10.04 DVD, we see all the .deb packages for installation . (you can see the kernel image listed there).
But, in 12.04, The DVD version doesn't have an text mode installer. Though the page still saying The combined install/live DVD allows you either to install Ubuntu permanently on a computer, or (by entering 'live' at the boot prompt) to try Ubuntu without changing your computer at all. This doesn't mean it has a text installer.
Why? Because it lacks the .deb files required for installation.... You can see some .deb files there but those are Libreoffice languages files and some other packages. It lacks the complete package suit need for installation, such as kernel images.
The change in policy happened since Ubuntu 11.10. 11.10 excluded this feature for maintainability of the DVD image and from then DVD image becomes just an extension of the CD image which includes some more softwares (like gimp, pitivi) and full language packs. The release note is saying this
In Ubuntu 11.10 there is now a revised, smaller (in size) DVD based on community feedback over the last few cycles. This new DVD has a more manageable size of 1.5G, and is an extension of our current CD image that includes all the language packs and some other useful applications, such as Inkscape, GIMP, Pitivi, and a more complete LibreOffice suite.
If you are looking for alternate installer. You can Look at this page for 12.04, which lists all the versions of the release. Take note that, the alternate installer images are will not be in the next Ubuntu releases. As Ubuntu mailing list saying this
is no longer a traditional CD sized image, DVD or alternate image, but
rather a single 800MB Ubuntu image that can be used from USB or DVD.
Hope this will help.