The first linked article talks about storage, not generation - is it the correct link? If we can get solar into the $0.02 - $0.04 range we'll have largely won the battle.
On shrinking wilderness, I'm not sure about some of the methodology in that paper. For land use in agriculture it seems to have tailored the timescale studied to support the theory that we're using less land for agriculture, but even the selective charts show we're almost at peak corn acreage and headed up-and-to-the-right. The argument about saying cubic yards of wood production per hectare of forest is going up was missing a timescale, and charting wood used per dollar of GDP doesn't really tell us anything about how much wood is actually being used, it just makes a chart that looks like its heading in the right direction. I think the US may be seeing less land under agriculture, but I think a lot more food is being imported from Central & South America, and Asia, areas that were not discussed in relation to area under agriculture. I didn't look up the reputation of thebreakthrough.org, but the paper read somewhat like a "we're doing fine - stop worrying" study influenced by parties that don't want rapid change.
There have been some major wins on the wilderness vs. non-wilderness front, though. Many waterways in North America is probably cleaner than it was 30 years ago, (think of the Great Lakes, and around NYC. I'm not sure about the Mississippi, Columbia, or Colorado river systems). Acid rain on the east coast & central Canada has largely been dealt with, and some species are even coming back to places they've been gone from for years, (I caught a salmon on vacation in BC last year for the first time in 20 years).