"City officials said they expect to file court documents to take over at least some of the 21-acre site in the coming weeks and have $97 million set aside to buy the properties and help landowners relocate. The city made offers to all 23 landowners on the site..."
I don't know how much any particular owner was offered, but this seems to suggest that the average total compensation offered each owner was north of $4 million.
The site is 21 acres, and that suggests that the property was valued, on average, at nearly $5 million per acre.
This is near waterfront in Southeast Washington. Although waterfront property is inherently valuable, Southeast Washington in general is not a very good area.
It appears that the city has at least attempted to treat the owners fairly.
You are making it sound like raw land without improvements. I don't know this area but you can put a hefty apartment building on an acre and $5 million for such a building might be a gross undervaluation. At today's real estate prices it does not take much of a building to be worth $5 million. Particularly on the waterfront.
And a lot of this money sounds like it is intended for the relocation of occupants who may or may not be the owners. If tenants get a bunch of this money for relocation costs then the owners will obviously be getting less.