I think the most odd thing is the cheap hardware store greenhouses for outdoor dining that are shown. I guess those patio heaters don't really do the trick do they?
If you build a greenhouse around your outdoor dining area, is it an outdoor dining area any more?
Indoor Plexiglass partitions provide isolation too but the level of isolation is more limited. Plus the air in a smaller indoor location is recirculated between partitions, whereas outdoors it is ostensibly exchanged at much higher rates.
Which makes me wonder, can't we build indoor booths?
The catch would be one would also need a HVAC that can exchange air outside the booths at high throughputs like aircraft cabins.
ACPH = air changes per hour = 60 * Q / L where Q = volumetric flow (ft3/min), L = ft3.
Aircraft cabin ACPH are around 20-30 (and through a HEPA filter) [1], while a restaurant dining area is 8-12 [2] (many assumptions here, like airtightness, etc), and no HEPA.
[0] https://www.timeout.com/chicago/news/dine-and-drink-in-a-pri...
[1] https://www.iata.org/contentassets/f1163430bba94512a583eb6d6...
[2] https://www.engineeringtoolbox.com/air-change-rate-room-d_86...