I don't disagree with you, but to give a bit of colour to the counterargument, as I understand it, we now have maybe 5 decades of experience which suggests that the "sharing" approach doesn't work at scale. In general, if you want to see wildlife in western Europe you go to a nature reserve, not a farm, because "spared" land will have nature but "shared" land increasingly won't. Of course there are some individual farmers who are doing great work and bucking that trend, but so far no one has found a magic formula that allows land to both be subject to intensive agriculture, and also support historically normal levels of wildlife. Or maybe someone has, but if so they've failed to convince farmers to adopt it unilaterally, or governments to impose it as policy.

So arguably the evidence we have is that if you consider only things that farmers like to be politically practical, then we're likely to see wildlife declines continue indefinitely.

That is of course why many people are looking for solutions that don't depend on the consent of the agricultural industry. One approach is to go over their heads and appeal directly to government e.g. the biodiversity COP agreement requiring 30% of land to be set aside for nature. Another is to hope that technological breakthroughs (e.g. precision fermentation) can fundamentally alter consumer demand for food products in a way that makes them much less land intensive (primarily by cutting out meat and other animal products, which use a disproportionate amount of land when farmed extensively, and produces a disproportionate amount of pollution when farmed intensively).

Of course, in the short term, the practical answer is "do both, wherever possible". Conservation organisations should be encouraged to purchase land so that it can be managed directly for wildlife. Farmers should be encouraged to adopt wildlife-friendly practices as much as possible. Governments should be encouraged to consider wildlife conservation a goal in itself when designing incentive schemes for the agriculture industry, and the taxpayers who directly fund much agriculture through subsidies should be encouraged to hold them accountable for their progress in this area.

Easier said than done, of course, but as the original article makes clear, the status quo is chronic failure, and there's no reason to suppose that can be changed within the current paradigm.