Then you just get devs rushing out changes before the freeze…

As a developer I don't see why I would rush out a change before the freeze when I could just wait until after. Maybe a stakeholder that really wants it would press for it to get out but personally I'd rather wait until after so I'm not fixing a bug during my holiday.

and stampeding changes in after the thaw, also leading to downtime. so it depends on the org, but doing a freeze is still reasonable policy. Downtime on December 15th is less expensive than on black Friday or cyber Monday for most retailers, so it's just a business decision at that point.