Even small scale production far outstrips the carbon footprint of a plant-based diet. There's no reason to fully substitute "meat" with Impossible products. Those products are designed for meat-eaters to help them transition to plant-based diets.
Once you get used to a plant-based diet the idea of "simulated meat" is absurd and not desire-able.
It's not for everyone; there are people whose cultures or physical needs prevent them from adopting such a diet and far be it from me or anyone else to dictate their diets for them.
However there remains the fact that beef production is unsustainable. Nearly 80% of our plant-based production goes to livestock feed. That's land that could be used to feed humans. And we'd use less land to do so. Instead the US and Canada have been increasing investments in the beef industry which is going to places like Brazil where they continue to slash and burn Amazon rain-forest in order to keep up the increasing demand for livestock feed.
The problem is a demand-side issue. Subsidized access to beef products has led to consumer perception that beef products are an affordable and accessible luxury. If we could even figure out what "sustainable beef" looks like it would be incredibly expensive and hardly available to anyone. The beef industry doesn't want that: it needs grocery and restaurant chains and ever-increasing consumer markets for its products to continue to grow its profits.
Which means continued deforestation, CO2 emissions, and lower sequestration rates.
I think subsidies should be removed and investment in plant-based alternatives continue in order to lower demand without price-shocks and panic. Once people realize how freaking expensive their dietary choices really are we might see the scales tip back. But we won't see that happen if governments and banks continue to artificially prop up low prices.