Are there examples of where this was done? I would love to know how fast it occurs, and see a graph of adoption/change over time.

I would imagine 5-10% of people would sell (to the developer) immediately. But those lots probably wouldn't be adjacent. Maybe after 3-5 years, enough adjacent lots could be found to make it appealing to a developer. (The developer wants economy of scale, and economy of multiple units sharing common space.) Where is the tipping point?

If the developer offered to buy homes at 20% over market rate, I wonder how the graph would change, vs. market rate.

But the developer needs to start buying immediately, yet can't recoup their investment for several years. They may not like that.