Everything that costs will cost to the degree that it costs. Putting the chocolate milk on the top shelf is enough to encourage children to buy less chocolate milk. The data you're talking about? The place I work at is the one doing the hard boots on the ground labor for aerial data, and from that perspective nothing is easy or free.

One can make great arguments about why people should have access to data notwithstanding all risks, but surely not that security by obscurity is mere illusion.

It doesn't work like that. The vast majority of the time it's regular stupid people that are doing the heavy lifting (often unwittingly) for state actor operations.

So yes, security by obscurity works. It makes the state actor's job that much harder.

They aren't. Wikipedia has been taken over by special interest groups and political agencies for a long, long time now.