I am trying to preorder Turboxtax. Even though I click on the line that says "I'd like to order a CD" the cart always comes up only with the Download version

[DoninGA]

It should still be the CD since the description includes both Windows and Mac whereas if it was a download it would only describe it as Win for Windows download or describe it as Mac for a Mac download, eg TURBOTAX DELUXE TAX YEAR 2017 WIN DOWNLOAD

This is a description for a Deluxe CD - TURBOTAX DELUXE TY2017 W/STATE DOWNLOAD WIN/MAC

[Critter]

The CD has both WIN & MAC on it ... this is what the order screen looks like ...

[Critter]

And I do believe that  they will also put downloads of both programs in your download file even if you get the CD ... they started it a couple of years ago so if you get a computer later that doesn't have a CD drive or the CD is lost or broken you still have access without going thru the trouble of contacting TT support later ... also access to the downloads happens before the CD gets mailed so you have access to it sooner.

[SteamTrain]

...It's not clear to me that download is available  with a normal CD pre-order . on the single-purchase page.

Yes...they have historically included a download copy if you order the CD thru TTX Advantage.  That program does an auto-order (and auto-charge) every year ...but (opinion) that's mostly for type A people who have to have it Right Now, not realizing the software is extremely buggy until late January or Feb anyhow  (more opinion).