If they're not taking on any of the employees, what are their costs? It's not clear that they're even keeping the website up or that it won't be a rather radically different product. All they've said is that it will be a 'cloud-based version of Digg' which means nothing.
It's probably a brand they're slapping onto something they already have in the works. How is it going to cost them a lot more to take it over?
To take over something like Digg? Everything costs.
Legal costs. Infrastructure costs. Clearing out employees and transitioning with new employees to take over and operate it. New product development to change the product into whatever they have in mind.
It's ridiculously easy to blow $500k doing nothing in tech when salaries run $100k with total compensation. And that's just the employee costs.
It'll cost Betaworks several million dollars to get Digg the way they want it, all in, including the purchase price.
It's probably a brand they're slapping onto something they already have in the works. How is it going to cost them a lot more to take it over?