Dynamicland is bootstrapped in a sense, [0] the same way you write the first compiler/interpreter for your code in another language then later write it in it's own language. The code running the camera and projector systems is also running from physically printed programs in one of the videos you can see a wall that's the core 'OS' so to speak of Dynamicland.

I think the vision is neat but hampered by the projector tech and the cost of setting up a version of your own, since it's so physically tied and Bret is (imo stubbornly) dedicated to the concept there's not a community building on this outside the local area that can make it to DL in person. It'd be neat to have a version for VR for example and maybe some day AR becomes ubiquitous enough to make it work anywhere.

[0] Annoyingly it's not open sourced so you can't really build your own version easily or examine it. There have been a few attempts at making similar systems but they haven't lasted as long or been as successful as Bret's Dynamicland.