Valve ban advertising-based business models on Steam, no forced adverts like in mobile games
(www.gamingonlinux.com)
What he means is, when gaben our lord an saviour dies, his majority shares ownership will be transferred to his inheritors.
The question "do they want to own and do they understand Valve or just see a big pile of cash?" will be answered then and there.
Which can very well result in an IPO.