Yes, my response was about Dante in general. If there are limits to the I/O card of the console (like there are with Yamaha MY cards) that would be the limit on channels. Both Dante as a network, and the Dante VSC support 64x64 at 48k with a GB connection.
The DN9650 literature claims 72x72 channels, but that takes 3 AES50 streams, leaving only the onboard I/O of the Pro 1 as inputs. If you use one of the AES50 streams for more inputs that may limit the 9650 to only 48 channels.
It is true that the DN9650 can take three AES50 streams, but at least the older Dante cards were still limited to 32x32 at 48K. I own two.
Maybe the new Dante card can do more? I haven't seen any in the wild yet and I was hoping someone who knew more than I did would chime in as I am interested in it as well and can't seem to find any specifics online regarding the card options. Probably due to phone call...
As Jelmer mentioned they did eventually activate all six AES50 ports on the PRO1. I had one that I had previously replaced with a PRO2c for the exact reason you mentioned (limited IO options and channel counts if using DN9650.) Since they improved the situation, I just bought a new PRO1 and took delivery yesterday.
A slick little desk, combined with a DN9650/Dante and a DL251 stagebox gives you a tiny but powerful live audio and multitracking rig.