The current owner can no longer afford the taxes and is forced to sell whether or not they want to. The developer can position themselves as the “highest bidder” by an extremely small margin over the property’s historical value, denying the current owner the windfall from the recent spike in land value. Despite the increased land value, no one else will be interested in purchasing the property at this valuation until the developer’s project is complete, as the project itself is the cause for the spike.
This is effectively eminent domain for private developers. If you’re a homeowner and you’ve been paying your property taxes just fine for the past decade on a $40,000/year salary, you shouldn’t suddenly become unable to afford to live there because someone said you live in a “hot area” or whatever.