Just to make things easier for people.
The video talks about the glut of micro units having issues selling due to how undesirable they are for people actually living in them and not aligning with a more realistic price.
The numbers on why a lot of people can't hold onto these investments:
Shrinking units, the ones discussed in the video is around ~300sqft:
Substantially less of newer units are owner occupied:
If you're referring to combining units I don't think it'll really be practical. The 300sqft mark is on the lower end of what is technically okay for people with some heavy consideration into functional design and lifestyle. Essentially a single person who probably spends a lot of time outside.
This is a pretty good video(13:03) on the topic .