Are you reading a different quote than me? He talks about consoles in plural, and continues to say, that they've released the 'SAD' and shown another console. That's neither confirming that he meant "exactly two consoles" or that there's no more consoles in the works.
I'm not hoping for another console. The entire notion of a low-end next-gen console is a waste of resources to be honest, but in my eyes, Phil Spencer has answered like every other high-level manager, that doesn't want to say anything of note.
edit:
Matt Booty also refuses to say anything concrete:
"<Booty> We're not talking about more than what we showed in the video, and what Phil talked about. Project Scarlett is our console plan headed into 2020.
<Interviewer>You did say console not consoles plan there.
<Booty>Scarlett is our console plan going into 2020."