I actually anticipate Apple releasing a 120Hz ProMotion display. I mean, everything else has it (iPad Pro, iPhone Pro, MacBook Pro), so I think eventually it's coming. It won't be 144+ Hz, as clearly anything that high is targeted at games. But I do believe it's coming at some point.It is not comparable because mobile devices like Android smartphones had 120hz screens for years, thus Apple had to respond to keep their product competitive.
Professional / productivity monitors that Apple is competing against are all 60hz, even $5000+ monitors from Eizo and Asus.
The only monitors that are 120hz or higher are all gaming monitors and that is not the competition of Apple their monitors. So I don't believe those "promotion" rumours that people are talking about if you look at the current market.
Now, do I expect a 32" 6K 120Hz display this spring? No. I don't think (and someone correct me if I'm wrong) one Thunderbolt 4 connection has enough bandwidth for that. 27" 5K at 120Hz? Yeah, that might be possible since I've already got two 5K 60Hz ASDs running off one Thunderbolt 4 connection, though I do believe there's some compression involved.
But expect 120Hz displays from Apple to command a significant price premium over 60Hz models.