Flippa was very good when it was sitepoint. It can more likely be bought. But I can't guess when.
Sedo may be interested to buy it. Godaddy will likely to have a bigger budget for it.
Sedo can make it more profitable than Godaddy. Because Sedo already sells websites, despite not many people know. Godaddy doesn't sell websites. There are not too many website+domain marketplaces in the size of Sedo. But it can be bought by a smaller player. It's difficult to guess.
Running a website marketplace is more complicated than a domain marketplace. Website has more disputable details during and after the sale. Domain and website marketplaces must and will eventually use only crypto currency.