Would AX be incompatible, even for AirTunes, with a 802.11b AC?

Question

My main router at home is a Netgear WGT624. From reading the discussions (and the user guide) I've learned that AX cannot extend my wireless network because the WGT624 doesn't support WDS.
OK, I thought, then I'll run an Ethernet cable from the Netgear router to my old iBook. It has a 802.11b original AC installed. I'll set it up as a base station. And then I'll connect the AX to that in client mode so I can at least have AirTunes.
Well, the iBook is putting out a very nice signal. But AX can't connect. Flashing amber. So is this what the AX User Guide means when it says "If your computer has +an Airport Extreme Card installed+ you can use AirTunes" (p. 18)?
And, does this mean that if I bought a refurbished 802.11g AC and put it into my other spare machine, a later eMac that takes the g card, that I could turn that into a base station and finally have AirTunes? In fact, wouldn't it mean I could extend the wireless network because the Extreme card supports WDS?
(Or should I just replace my Netgear with another AX?)

Answer 1

From reading the discussions (and the user guide) I've learned that AX cannot extend my wireless network because the WGT624 doesn't support WDS.
The AX can not wirelessly extend the Netgear's network but the AX can still join the Netgear's network as a wireless client. Then the AX's music streaming and printing services will be available to anyone connected to the Netgear (via wireless or Ethernet).