Because you do not need a CO2 gas tank to run a planted tank!
And a non CO2 approach requires no test kits, and no water changes.

The solar tubes I've seen here in action.
They used a large fesnel lens and fiber optic cables to channel it.
It's not cheap though.

Some shade cloth and some glass awnings would do the trick for that and be much cheaper.

But I still would need to the solar panels for energy to drive the tank's pumps.
There would be no heater(in CA, it would not matter).

Maybe you like CO2, that's fine, but the goal here is to reduce the inputs and outside aspects, including my meddling hands

You could use the DIY method, that would work well, especially if you could use the fermented brew afterwards.

I do agree with you about the buildings.
Make it right and it should last.
While some of the general ideas are pretty good and can be applied, some folks get way to carried away and do not think about the longer term aspects.
We have started working towards this goal for a client's property.
It has the makings to get close to many of the goals.

Regards,
Tom barr